THE DEAF AS A PERMANENT ELEMENT OF THE POPULATION
Increase in the Number of the Deaf in Relation to the Increase in the General Population
Are the deaf to be a permanent element in the constitution of the population? Are they always to be reckoned with in the life of the state and the regard of society? Would it not be well to inquire whether or not deafness may be eliminated, or at least reduced to an appreciable degree? These are questions that present themselves at the outset in a consideration of the relation of the deaf to society, and to them we now devote our attention.
Our first inquiry in the matter is directed to the question whether deafness as a whole is increasing, decreasing or remaining stationary, in relation to the general population. To determine this, we have recourse to the census returns of the deaf in connection with those of the general population. Unfortunately, however, comparisons of the different censuses respecting the deaf are not altogether to be depended upon, for the reason that they have not always been taken on the same basis, and conclusions from them consequently have to be accepted with qualifications. Special census returns of the deaf have been made since 1830; but the censuses of 1830-1870 purport to be of the deaf and dumb; the census of 1880, of the deaf who became deaf under sixteen years of age; that of 1890, of the deaf and dumb; that of 1900, of the totally deaf; and that of 1910, of the deaf and dumb. The results thus obtained are in the main analogous, but there are a certain number of cases included on one basis that would be excluded on another, and vice versa.[15]
Taking the statistics as they are, we have the following table,[16] which gives the number of the deaf as found in the several censuses, according to the bases upon which they were made, together with the ratio per million of population.
NUMBER OF THE DEAF ACCORDING TO THE CENSUSES OF 1830-1910
| Year | Number | No. per Million of Population |
| 1830 (the deaf and dumb) | 6,106 | 475 |
| 1840 (the deaf and dumb) | 7,665 | 449 |
| 1850 (the deaf and dumb) | 9,803 | 423 |
| 1860 (the deaf and dumb) | 12,821 | 408 |
| 1870 (the deaf and dumb) | 16,205 | 420 |
| 1880 (deafness occurring under sixteen) | 33,878 | 675 |
| 1890 (the deaf and dumb) | 40,592 | 648 |
| 1900 (the totally deaf) | 37,426 | 492 |
| 1910 (the deaf and dumb) | 43,812 | 476 |
From this table there appears to be a steady decrease in the number of the deaf in relation to the general population from 1830 to 1860, this latter year seeming to be the low water mark. From 1860 to 1870 there is a slight increase, and from 1870 to 1880 a very large one, due to some extent to the method of taking the census. From 1880 to 1890 there is a certain decrease, though the proportion is still very high. From 1890 to 1900 there is a very considerable decrease, probably indicating a return to true conditions; and a not negligible decrease from 1900 to 1910.
On the whole, with respect to these statistics, probably the most that we can safely say is that deafness is at least not on the increase relatively among the population, while there is a possibility that at present it is decreasing. For further determinations, we shall have to seek other means of inquiry.
The Adventitiously Deaf and the Congenitally Deaf
We may perhaps best approach the problem of deafness as an increasing or decreasing phenomenon in the population, if we think of the deaf as composed of two great classes: those adventitiously deaf, that is, those who have lost their hearing by some disease or accident occurring after birth, and those congenitally deaf, that is, those who have never had hearing.[17] In regard to the former class, it follows that we are largely interested in the consideration of those diseases, especially those of childhood, which may affect the hearing, and in their prevention or diminution we can endeavor to ascertain how far there are possibilities of reducing the number of the deaf of this class. In the latter case we are called upon to examine some of the great problems involved in the study of heredity, especially in respect to the extent that the offspring is affected by defects or abnormalities of the parent, and to see what, if any, means are at hand to alter conditions that bring about this form of deafness. We shall first discuss the causes of adventitious deafness, together with the possibilities of its prevention and the likelihood of its diminution, and then consider the questions involved in congenital deafness.
Adventitious Deafness and its Causes
From three-fifths to two-thirds of the cases of deafness are caused adventitiously—by accident or disease. To accidents, however, only a very small part are due, probably less than one-fiftieth of the entire number.[18] Nearly all adventitious deafness results from some disease, either as a primary disease of the auditory organs, or as a sequence or product of some disease of the system, often one of infectious character, the deafness thus constituting a secondary malady or ailment. The larger portion is of the latter type, probably less than a fourth resulting from original ear troubles.[19] In either case deafness occurs usually in infancy or childhood, and does its harm by attacking the middle or internal ear.
From diseases of the middle ear results over one-fourth (27.2 per cent, according to the census) of all deafness, and from diseases of the internal ear, one-fifth (20.7 per cent), very little (0.6 per cent) being caused by disorders of the outer ear. Of the classified cases of deafness, according to the census, 56.3 per cent are due to diseases affecting the middle ear, and 42.7 per cent to diseases affecting the internal. Of diseases of the middle ear, 72 per cent are of suppurative character, often with inflammation or abscess, and 28 per cent non-suppurative, or rather catarrhal in character. Of diseases of the internal ear, 89 per cent are affections of the nerve, and 10 per cent of the labyrinth. It is to be noted that when the affection is of the internal ear, the result is usually total deafness.
By specified diseases, the leading causes of deafness are scarlet fever (11.1 per cent), meningitis (9.6), brain fever (4.7), catarrh (3.6), "disease of middle ear" (3.6), measles (2.5), typhoid fever (2.4), colds (1.6), malarial fever (1.2), influenza (0.7), with smaller proportions from diphtheria, pneumonia, whooping cough, la grippe, and other diseases. A large part of deafness is seen to be due to infectious diseases, the probabilities being that fully one-third is to be so ascribed, with one-fifth from infectious fevers alone.
After birth and under two years of age, the chief causes of deafness are meningitis, scarlet fever, disease of middle ear, brain fever, and measles. From two to five scarlet fever and meningitis are far in the lead, with many cases also from brain fever, disease of middle ear, measles, and typhoid fever. From five to ten scarlet fever alone outdistances all other diseases, followed in order by meningitis, brain fever and typhoid fever. From ten to fifteen the main causes are meningitis, scarlet fever, brain fever, and catarrh; from fifteen to twenty catarrh and meningitis; from twenty to forty catarrh, colds and typhoid fever; and from forty on, catarrh.
The following table[20] will show in detail the several causes of deafness and their respective percentages.
CAUSES OF DEAFNESS
In fairly approximate agreement with the returns of the census, are the records of the special schools for the deaf in respect to the causes of deafness in their pupils, with information also as to the amount from the minor diseases. The following table will give the causes by specific diseases, as found in one school, the Pennsylvania Institution, for two years:[21]
CAUSES OF DEAFNESS OF PUPILS IN PENNSYLVANIA INSTITUTION
| 1906 | 1907 | |||
| Per Cent | Per Cent | |||
| Total number | 510 | 100.0 | 500 | 100.0 |
| Born deaf | 213 | 41.8 | 206 | 41.2 |
| Scarlet fever | 43 | 8.2 | 47 | 9.4 |
| Meningitis | 36 | 7.1 | 40 | 8.0 |
| Falls | 24 | 4.7 | 25 | 5.0 |
| Diseases of ear and throat | 13 | 2.6 | 23 | 4.6 |
| Catarrh and colds | 13 | 2.6 | — | — |
| Measles | 18 | 3.5 | 18 | 3.6 |
| Brain fever | 17 | 3.3 | 16 | 3.2 |
| Convulsions | 14 | 2.8 | 13 | 2.6 |
| Abscesses | 10 | 2.0 | 12 | 2.4 |
| La grippe | 10 | 2.0 | 7 | 1.4 |
| Accidents (not stated) | 9 | 1.8 | 7 | 1.4 |
| Whooping cough | 7 | 1.4 | 7 | 1.4 |
| Typhoid fever | 7 | 1.4 | 6 | 1.2 |
| Diphtheria | 6 | 1.2 | 6 | 1.2 |
| Mumps | 5 | 1.0 | 5 | 1.0 |
| Paralysis | 5 | 1.0 | 4 | 0.8 |
| Marasmus | 2 | 0.4 | 4 | 0.8 |
| Pneumonia | 4 | 0.8 | 2 | 0.4 |
| Dentition | — | — | 2 | 0.4 |
| Dropsy of blood | 2 | 0.4 | — | — |
| Chicken pox | 1 | 0.2 | 1 | 0.2 |
| Poisoning | 1 | 0.2 | 1 | 0.2 |
| Intermittent fever | 1 | 0.2 | 1 | 0.2 |
| Blood clotting on brain | 1 | 0.2 | — | — |
| Cholera infantum | 1 | 0.2 | — | — |
| Gastric fever | — | — | 1 | 0.2 |
| Sickness (not stated) | 10 | 2.0 | 8 | 1.6 |
| Unknown | 37 | 7.3 | 38 | 7.6 |
Possible Action for the Prevention of Adventitious Deafness
In respect to present activities for the prevention of adventitious deafness, we find the situation very much like that of marking time. Deafness, since the beginning of time, has largely been accepted as the portion of a certain fraction of the race, and any serious and determined efforts for its eradication have been considered for the most part as of little hope.[22] With the auditory organs so securely hidden away in the head, entrenched within the protecting temporal bone, and with their structure so delicate and complicated, the problem may well have been regarded a baffling one even for the best labor of medicine and surgery. Hence it is that after deafness has once effected lodgment in the system, a cure has not usually been regarded as within reach, though for certain individual cases there may be medical examination and treatment, with attempts made at relief. For deafness in general, it has been felt that there has been little that could be done in the way of prevention or cure beyond the preservation of the general health and the warding off of diseases that might cause loss of hearing.
As a matter of fact, however, altogether too little attention has been given hitherto to the possibilities of the prevention of deafness. Without question there is much at the outset that can be accomplished towards the prevention of those diseases that cause deafness. A large part, perhaps fully a third, as we have seen, are due to infectious diseases, and it is probably here that measures are likely to be most efficacious. A considerable portion likewise are the result of diseases affecting the passages of the nose and throat, and help should be possible for many of these if taken in hand soon enough. In certain diseases also, as scarlet fever, measles, typhoid fever, diphtheria, and others, there are not a few cases which, so far as deafness as a development is concerned, would prove amenable to skillful and persistent treatment. At the same time due attention to primary ear troubles would in a number of instances keep off permanent deafness. Indeed, it is possible that some thirty or forty per cent of adventitious deafness is preventable by present known means.[23]
Aside from direct medical treatment for those diseases that cause deafness, there are other measures available in a program for the prevention of deafness. One of the foremost essentials is the report to the health authorities of all serious diseases that are liable to result in deafness. In this way proper medical care may be secured, and due precautions may be taken to isolate infectious cases. Even with meningitis, which is so hard usually to deal with and which is so severe in its ravages, there is often some concomitant trouble, and if made notifiable in all cases deafness from it might be checked in no inconsiderable measure. The report of births is also especially needed, and as it becomes obligatory in general, with the consequent detection of physical ailments or disabilities, early cases of deafness may come increasingly to notice, and timely treatment may be availed of. Particular attention is likewise necessary in respect to the medical examination of school children. The proportion of such children with impaired hearing is not slight, even though no great part of them become totally deaf. A committee on defective eyes and ears of school children of the National Educational Association in 1903 found that of 57,072 children examined in seven cities, 2,067, or 3.6 per cent, were extremely defective in hearing.[24] An investigation of the school children in New York City has disclosed the fact that one per cent have seriously defective hearing.[25] Under proper and adequate medical inspection of schools, not only would the need of treatment for adenoids and similar troubles be brought to light, with the result that a number of incipient cases might be stopped in time, but in some instances of deafness already acquired beneficial treatment might be possible.[26]
There is thus a considerable sphere for action towards the prevention of adventitious deafness both by legislation and by education. For the ultimate solution of its problems, however, we have to look mainly to the medical profession. In recent years medical science has won some great triumphs, and in the field of the prevention of deafness no little may be in store to be accomplished in the years to come.[27] Even now, with more particular attention to the diseases of children, and with stronger insistence upon general sanitary measures, the probabilities are that there is less deafness from certain diseases than formerly—a matter which we are soon to consider.
Though as yet there has been little direct action for the prevention of adventitious deafness, there is an increasing concern in the matter, and in this there is promise. By medical bodies in particular is greater attention being given to the subject,[28] and in the widening recognition of their part as guardians of the public health it may be possible for them to do much for the enlightenment of the public. In one state legislative action has been taken expressly for the protection of the hearing of school children. This is Massachusetts, which requires the examination of the eyes and ears of the school children in every town and city, the state board of education furnishing the tests.[29] In some states also general inspection of schools is mandatory by statute, and in others permissive, while in several there are local ordinances with the force of a state law.
In combating adventitious deafness, then, our attack is to be directed in the largest part upon those diseases, especially infantile and infectious diseases, that cause deafness; and it is upon the checking of their spread that our main efforts for the present have to be concentrated. At the same time the better safe-guarding of the general health of the community will insure a proportionate diminution of deafness. Beyond this, we will have to wait upon the developments of medical science, both in the study of the prevention of diseases and of their treatment; and can trust only to what it may offer.[30]
Adventitious Deafness as an Increasing or Decreasing Phenomenon
Our main interest in the problem of adventitious deafness lies in the possible discovery whether or not it is relatively increasing or decreasing among the population, and in what respects signs appear of a diminution. We have just seen the likelihood of a decrease from certain causes; but we are to find what is indicated by statistical evidence.
To be considered first is adventitious deafness as a whole. Respecting it our only statistics are in the returns of the censuses since 1880, the different forms of deafness not being distinguished before this time. The following table will show the number of the adventitiously deaf as reported by the censuses of 1880, 1890 and 1900, with their respective percentages and ratios per million of population.[31]
NUMBER OF THE ADVENTITIOUSLY DEAF IN 1880, 1890 AND 1900
| Total Number | Adventitiously Deaf | Percentage | Ratio per Million of Population | |
| 1880 | 33,878 | 10,187 | 30.1 | 20.3 |
| 1890 | 40,562 | 16,767 | 41.1 | 26.8 |
| 1900 | 37,426 | 18,164 | 48.4 | 23.9 |
From this it appears that adventitious deafness is increasing in relation to total deafness, which is most likely the case, as congenital deafness, as we shall see, is evidently decreasing. Whether or not adventitious deafness is increasing in respect to the general population, the table does not disclose definitely. The statistics probably are not full enough to afford any real indication yet.
Our next inquiry is in respect to the increase or decrease of adventitious deafness from the several diseases individually, which is, upon the whole, the more satisfactory test. Here also, unfortunately, our statistics are very limited, and our findings will have to fall much short of what could be desired.
The following table, based on the returns of the censuses of 1880, 1890 and 1900, so far as the approximate identity of the several diseases can be established, will give the respective percentages found.[32]
CAUSES OF ADVENTITIOUS DEAFNESS IN 1880, 1890 AND 1900
| 1880 | 1890 | 1900 | |
| Scarlet fever | 7.9 | 11.8 | 11.1 |
| Meningitis | 8.4 | 7.8 | 9.6 |
| Catarrh and catarrhal fevers | 0.9 | 3.3 | 3.6[33] |
| Diphtheria | 0.2 | 0.5 | —[34] |
| Abscess and inflammation | 1.0 | 2.5 | —[35] |
| Measles | 1.3 | 2.5 | 2.5 |
| Whooping cough | 0.5 | 0.8 | —[34] |
| Malarial and typhoid fevers | 1.7 | 1.8 | 3.6 |
| Other fevers | 1.1 | — | 2.0 |
In this table the most noticeable thing is perhaps the persistency with which we find most of the diseases to recur, with apparently no great change, while in certain ones, as catarrh and malarial and typhoid fevers, there seems to be rather an increase. It would be best, however, not to place very great confidence in these figures, but, so far as the census reports are concerned, to wait for more precise and uniform statistics.
We have, further, the statistics published in the reports of certain schools for the deaf. While these are perhaps not of sufficient extent to warrant full conclusions, they may be regarded as quite representative;[36] and though to be taken with something of the caution as the census figures, they may serve to throw some light upon the situation. Comparison of the proportions of pupils deaf from the several diseases at different times may be made in two ways: by finding the respective proportions over a series of successive years from a certain time back down to the present, and by contrasting the proportions in two widely separated periods, one in the present and one in the past. These will be taken up in order.
The following tables give the percentages of cases of deafness in pupils from the important diseases as found in six schools in successive years: in the New York Institution in the total annual attendance from 1899 to 1912; in the Michigan School in the total biennial attendance from 1883 to 1912; in the Pennsylvania Institution in the number of new pupils admitted quadriennially from 1843 to 1912; in the Western Pennsylvania Institution in the number admitted biennially from 1887 to 1912; in the Maryland School in the number admitted biennially from 1884 to 1911; and in the Wisconsin School in the number admitted biennially from 1880 to 1908.
I. CAUSES OF DEAFNESS IN NEW YORK INSTITUTION FROM 1899 TO 1912
| 1899 | 1900 | 1901 | 1902 | 1903 | 1904 | 1905 | 1906 | 1907 | 1908 | 1909 | 1910 | 1911 | 1912 | |
| Total Number | 466 | 476 | 481 | 477 | 464 | 503 | 508 | 510 | 543 | 555 | 565 | 570 | 546 | 518 |
| Congenital | 36.0 | 27.1 | 26.8 | 40.9 | 36.2 | 41.1 | 46.2 | 31.8 | 33.3 | 34.4 | 34.9 | 32.8 | 34.6 | 36.6 |
| Scarlet Fever | 11.4 | 10.1 | 8.9 | 7.1 | 6.5 | 6.9 | 6.5 | 4.9 | 5.3 | 5.0 | 5.7 | 6.1 | 5.7 | 5.0 |
| Meningitis | 9.5 | 9.4 | 7.7 | 7.9 | 7.8 | 7.9 | 11.0 | 12.2 | 16.8 | 18.6 | 17.7 | 17.9 | 19.0 | 19.7 |
| Brain Trouble | 10.1 | 9.2 | 8.3 | 8.1 | 7.2 | 5.9 | 5.9 | 7.1 | 9.0 | 8.3 | 8.7 | 8.3 | 8.0 | 8.9 |
| Falls | 9.0 | 7.2 | 5.4 | 4.5 | 3.9 | 4.2 | 3.8 | 5.2 | 5.9 | 6.1 | 6.0 | 5.1 | 5.5 | 5.6 |
| Measles | 5.1 | 3.8 | 3.8 | 2.1 | 3.9 | 4.5 | 4.1 | 4.1 | 4.8 | 4.7 | 4.4 | 4.6 | 0.2 | 0.7 |
| Typhoid Fever | 3.7 | 2.3 | 1.6 | 1.0 | 0.9 | 1.2 | 1.0 | 1.0 | 1.3 | 1.3 | 1.2 | 1.1 | 0.9 | 0.5 |
| Convulsions | 3.2 | 4.4 | 3.2 | 2.9 | 2.6 | 0.2 | 1.8 | 1.8 | 1.9 | 1.5 | 1.9 | 1.9 | 2.0 | 2.1 |
| Various Fevers | 2.5 | 1.5 | 1.4 | 1.0 | 1.7 | 1.6 | 1.6 | 1.6 | 1.5 | 1.3 | 0.7 | 0.5 | 0.5 | 0.7 |
| Catarrh | 2.3 | 2.1 | 1.9 | 1.8 | 1.6 | 1.2 | 1.0 | 2.0 | 1.9 | 1.9 | 1.4 | 0.8 | 1.0 | 0.5 |
| Diphtheria | 1.9 | 1.7 | 1.9 | 1.0 | 0.9 | 0.4 | 0.6 | 0.8 | 0.9 | 0.9 | 0.7 | 0.7 | 0.7 | 0.5 |
| Pneumonia | 1.5 | 0.8 | 0.8 | 0.6 | 1.1 | 0.2 | 1.0 | 1.1 | 1.1 | 0.9 | 1.1 | 1.1 | 0.7 | 0.5 |
| Whooping Cough | 1.7 | — | 1.6 | 1.2 | 1.1 | 1.0 | 0.8 | 0.6 | 0.9 | 0.9 | 0.5 | 0.5 | 0.5 | 0.2 |
| Miscellaneous and Unknown | 2.1 | 20.4 | 26.7 | 19.8 | 18.6 | 23.7 | 14.7 | 25.9 | 15.4 | 14.2 | 15.1 | 18.6 | 20.7 | 18.5 |
II. CAUSES OF DEAFNESS IN MICHIGAN SCHOOL FROM 1883 TO 1912
| 1883 1884 | 1885 1886 | 1887 1888 | 1889 1890 | 1891 1892 | 1893 1894 | 1895 1896 | 1897 1898 | 1899 1900 | 1901 1902 | 1903 1904 | 1905 1906 | 1907 1908 | 1909 1910 | 1911 1912 | |
| Total Number | 302 | 336 | 342 | 350 | 343 | 365 | 428 | 412 | 441 | 447 | 451 | 404 | 361 | 354 | 353 |
| Congenital | 7.0 | 18.8 | 23.1 | 26.3 | 24.2 | 26.3 | 25.2 | 30.3 | 28.8 | 31.5 | 32.8 | 36.6 | 35.7 | 35.0 | 31.2 |
| Meningitis | 28.8 | 28.1 | 23.1 | 23.1 | 21.3 | 15.8 | 15.6 | 14.5 | 10.2 | 9.2 | 4.6 | 8.6 | 9.5 | 8.8 | 8.2 |
| Scarlet Fever | 12.2 | 11.8 | 12.3 | 11.2 | 9.0 | 9.6 | 9.5 | 9.7 | 9.5 | 9.3 | 7.6 | 6.9 | 5.8 | 3.6 | 4.5 |
| Brain Fever | 6.2 | 6.5 | 4.8 | 3.7 | 5.2 | 6.9 | 6.6 | 6.3 | 5.4 | 3.8 | 3.8 | 2.7 | 2.5 | 2.3 | 1.0 |
| Typhoid Fever | 4.6 | 3.6 | 4.1 | 4.3 | 4.7 | 1.9 | 1.8 | 1.4 | 2.5 | 2.2 | 1.3 | 1.0 | 1.4 | 1.5 | 1.7 |
| Measles | 3.6 | 4.1 | 3.9 | 2.9 | 2.6 | 1.4 | 0.8 | 1.9 | 3.2 | 3.1 | 2.9 | 2.9 | 4.1 | 3.4 | 3.1 |
| Diphtheria | 0.6 | — | — | 0.3 | 0.3 | 0.3 | 0.2 | 0.2 | 0.4 | 0.2 | 0.4 | 0.5 | 0.2 | 0.3 | 0.3 |
| Catarrh | 0.6 | 0.6 | 0.9 | 0.8 | 0.9 | 1.1 | 1.9 | — | 2.9 | 3.5 | 3.3 | 2.8 | 1.9 | 2.5 | 0.8 |
| Various Fevers | 2.9 | 1.5 | 2.0 | 2.6 | 3.0 | 4.4 | 4.4 | 1.7 | 2.9 | 2.9 | 3.3 | 2.5 | 0.5 | 2.0 | 1.4 |
| Whooping Cough | 1.3 | 1.2 | 1.5 | 1.5 | 1.5 | 3.0 | 3.8 | 3.6 | 2.7 | 2.5 | 3.1 | 3.4 | 4.4 | 4.8 | 5.1 |
| Pneumonia | — | — | — | — | — | — | — | — | 0.2 | 0.2 | 0.4 | — | 0.7 | 0.6 | 0.8 |
| La grippe | — | — | — | — | — | — | — | — | 0.9 | 1.1 | 1.6 | 1.5 | 3.0 | 2.3 | — |
| Miscellaneous and Unknown | 32.2 | 23.8 | 24.3 | 23.3 | 27.3 | 29.3 | 30.2 | 30.4 | 30.4 | 31.5 | 34.9 | 30.6 | 30.3 | 32.9 | 41.9 |
III. CAUSES OF DEAFNESS IN PENNSYLVANIA INSTITUTION FROM 1843 TO 1912
| 1843 1846 | 1847 1850 | 1851 1854 | 1855 1858 | 1859 1862 | 1863 1866 | 1867 1870 | 1871 1874 | 1875 1878 | 1879 1882 | 1883 1886 | 1887 1890 | 1891 1894 | 1895 1898 | 1899 1902 | 1903 1906 | 1907 1910 | 1911 1912 | |
| Total Number | 90 | 111 | 125 | 143 | 167 | 152 | 150 | 178 | 282 | 233 | 261 | 207 | 248 | 250 | 239 | 240 | 282 | 152 |
| Congenital | 54.4 | 58.5 | 56.0 | 46.8 | 53.3 | 48.4 | 40.0 | 42.1 | 31.2 | 24.4 | 34.1 | 47.3 | 46.8 | 41.6 | 32.2 | 35.8 | 33.7 | 34.2 |
| Scarlet Fever | 13.3 | 18.0 | 12.8 | 16.8 | 9.6 | 19.7 | 16.0 | 18.6 | 18.1 | 13.7 | 14.9 | 14.0 | 14.1 | 11.2 | 6.3 | 10.4 | 3.9 | 5.2 |
| Meningitis | — | — | 0.8 | — | — | 2.0 | 1.3 | 9.6 | 18.1 | 25.7 | 16.4 | 5.8 | 5.6 | 7.6 | 8.4 | 7.1 | 17.4 | 15.1 |
| Measles | 1.1 | 2.7 | 1.6 | 2.8 | 2.4 | 3.3 | 4.0 | 1.1 | 1.7 | 2.6 | 1.9 | 3.9 | 3.2 | 4.4 | 4.6 | 4.5 | 3.5 | 3.9 |
| Whooping Cough | 2.2 | 0.9 | 0.8 | 0.7 | 1.2 | 0.7 | 1.3 | 0.6 | 0.3 | 0.8 | — | 0.5 | 0.4 | 0.8 | 1.7 | 0.7 | 2.9 | 1.3 |
| Catarrh | — | 0.9 | — | — | — | — | 0.7 | 0.6 | 2.1 | — | — | 3.9 | 4.8 | 6.8 | 4.2 | 1.2 | 2.5 | 1.3 |
| Brain Fever | — | — | 2.8 | 2.1 | — | 6.0 | 4.7 | — | — | — | 0.8 | 2.9 | 5.2 | 4.0 | 3.4 | 1.7 | 2.9 | 2.6 |
| Typhoid Fever | — | — | — | 1.4 | 0.6 | 0.7 | 2.6 | 2.7 | 2.1 | 2.6 | 3.4 | 2.9 | 3.6 | — | 2.5 | 0.7 | 3.9 | 1.3 |
| Diphtheria | — | — | — | — | — | — | 0.7 | — | — | — | — | 0.5 | 1.6 | 2.0 | 0.8 | 2.5 | 1.2 | 2.0 |
| Pneumonia | — | — | — | — | — | — | — | — | — | — | — | 0.5 | — | — | 0.8 | 0.4 | 1.2 | 4.8 |
| La grippe | — | — | — | — | — | — | — | — | — | — | — | — | 0.4 | — | 2.1 | 1.2 | 0.3 | — |
| Mis. and Unknown | 29.0 | 19.2 | 25.2 | 29.4 | 32.9 | 19.2 | 28.7 | 24.7 | 26.3 | 30.2 | 28.5 | 17.8 | 14.3 | 21.6 | 33.0 | 33.8 | 26.6 | 28.3 |
IV. CAUSES OF DEAFNESS IN WESTERN PENNSYLVANIA INSTITUTION FROM 1887 TO 1912
| 1887 1888 | 1889 1890 | 1891 1892 | 1893 1894 | 1895 1896 | 1897 1898 | 1899 1900 | 1901 1902 | 1903 1904 | 1905 1906 | 1907 1908 | 1909 1910 | 1911 1912 | |
| Total Number | 61 | 56 | 58 | 58 | 49 | 40 | 50 | 41 | 110 | 59 | 73 | 71 | 73 |
| Congenital | 24.6 | 14.3 | 20.7 | 32.8 | 46.9 | 40.6 | 40.0 | 31.9 | 38.2 | 25.4 | 30.1 | 40.9 | 36.5 |
| Scarlet Fever | 9.8 | 21.4 | 8.6 | 10.4 | 10.2 | 5.0 | 6.0 | 12.2 | 8.3 | 11.8 | 8.2 | 11.3 | 12.7 |
| Meningitis | 16.5 | 14.5 | 13.8 | 10.4 | 10.2 | 20.0 | 14.0 | 17.1 | 7.2 | 10.2 | 13.7 | 14.1 | 9.6 |
| Measles | 4.9 | 1.9 | 5.2 | 10.4 | 4.0 | — | 2.0 | 2.4 | 7.2 | 1.9 | 8.2 | 2.8 | 6.8 |
| Catarrh | 3.2 | — | 7.6 | 1.9 | 2.0 | 5.0 | 2.0 | 9.6 | 2.7 | 3.8 | 4.1 | 2.8 | 1.8 |
| Brain Fever | 6.5 | 5.4 | 1.9 | 1.9 | — | 2.5 | — | 4.8 | 2.7 | 5.1 | 2.8 | 1.4 | 4.1 |
| Typhoid Fever | — | 1.9 | 5.2 | — | 6.0 | 2.5 | — | — | 1.8 | 1.9 | 4.1 | 2.8 | — |
| Whooping Cough | 1.6 | — | 1.9 | — | 2.0 | — | 6.0 | 2.4 | 1.8 | 1.9 | 2.8 | — | 1.8 |
| Diphtheria | 1.6 | — | 1.9 | — | — | — | 4.0 | 2.4 | 1.8 | — | 1.4 | 1.4 | 1.8 |
| La grippe | — | — | — | — | 2.0 | — | 2.0 | — | — | 1.9 | — | — | — |
| Pneumonia | — | — | — | — | — | 2.5 | 2.0 | — | — | 1.9 | 1.4 | — | — |
| Miscellaneous and Unknown | 31.3 | 30.6 | 33.2 | 32.2 | 16.7 | 22.5 | 22.0 | 17.2 | 28.3 | 34.2 | 23.2 | 22.5 | 24.9 |
V. CAUSES OF DEAFNESS IN MARYLAND SCHOOL FROM 1884 TO 1911
| 1884 1885 | 1886 1887 | 1888 1889 | 1890 1891 | 1892 1893 | 1894 1895 | 1896 1897 | 1898 1899 | 1900 1901 | 1902 1903 | 1904 1905 | 1906 1907 | 1908 1909 | 1910 1911 | |
| Total Number | 28 | 27 | 25 | 25 | 29 | 30 | 30 | 39 | 29 | 30 | 28 | 41 | 32 | 135[37] |
| Congenital | 46.4 | 62.9 | 44.4 | 36.0 | 37.9 | 43.3 | 43.3 | 61.5 | 44.8 | 43.3 | 57.1 | 53.7 | 34.4 | 51.8 |
| Meningitis | 10.7 | 11.1 | 8.0 | 12.0 | 10.3 | 10.6 | 6.7 | 2.6 | 14.0 | 3.3 | 3.6 | 2.4 | 12.2 | 8.1 |
| Scarlet Fever | 10.7 | 7.4 | 12.0 | 16.0 | — | — | 6.7 | 5.2 | 3.5 | 10.0 | 7.2 | 9.6 | 3.1 | 1.4 |
| Measles | 3.6 | — | — | — | 3.5 | 3.3 | 6.7 | — | 3.5 | 3.3 | — | — | 3.3 | 2.2 |
| Diphtheria | — | — | — | — | 3.5 | 3.3 | 3.3 | 2.6 | — | 3.3 | 3.6 | — | — | 0.7 |
| Catarrh | — | — | — | — | 3.5 | 3.3 | 3.3 | 5.2 | 3.5 | — | — | — | — | — |
| Typhoid Fever | — | — | 4.0 | — | — | — | — | — | — | 6.7 | — | 2.4 | 3.1 | 2.2 |
| Whooping Cough | 3.6 | — | — | — | — | — | — | — | 3.5 | — | — | — | 3.1 | 1.4 |
| Pneumonia | 3.6 | — | — | — | — | — | — | — | 7.0 | — | 3.6 | 2.4 | 3.1 | 2.2 |
| Brain Fever | 7.2 | — | 4.0 | 8.0 | 3.5 | 3.3 | — | — | 7.0 | 3.3 | — | 4.8 | — | 2.9 |
| Various Fevers | — | — | 4.0 | 8.0 | 3.5 | — | — | 2.6 | — | 3.3 | 3.6 | 4.8 | — | 2.2 |
| Miscellaneous and Unknown | 14.2 | 18.6 | 23.6 | 20.0 | 34.3 | 32.9 | 28.1 | 22.0 | 16.7 | 23.5 | 21.3 | 19.9 | 37.7 | 24.1 |
VI. CAUSES OF DEAFNESS IN WISCONSIN SCHOOL FROM 1879 TO 1908
| 1879 1880 | 1881 1882 | 1883 1884 | 1885 1886 | 1887 1888 | 1889 1890 | 1891 1892 | 1893 1894 | 1895 1896 | 1897 1898 | 1899 1900 | 1901 1902 | 1903 1904 | 1905 1906 | 1907 1908 | |
| Total Number | 36 | 66 | 231[37] | 56 | 67 | 50 | 44 | 72 | 64 | 72 | 62 | 33 | 33 | 63 | 70 |
| Congenital | 14.3 | 31.8 | 35.1 | 35.7 | 49.3 | 38.0 | 50.0 | 40.3 | 53.1 | 52.7 | 64.3 | 33.3 | 48.4 | 34.9 | 40.0 |
| Meningitis | 27.7 | 33.3 | 37.7 | 33.9 | 28.3 | 32.0 | 15.9 | 12.5 | 31.2 | 19.4 | 16.1 | 9.1 | 3.0 | 6.3 | 5.7 |
| Scarlet Fever | 14.3 | 6.0 | 12.5 | — | 8.9 | 12.0 | 20.4 | 11.1 | 4.7 | 6.9 | 4.7 | 6.1 | — | 9.5 | 8.6 |
| Measles | 12.8 | 3.0 | 1.5 | — | 2.9 | — | 2.3 | 4.1 | 3.1 | — | — | 3.0 | 3.6 | 1.6 | 4.3 |
| Typhoid Fever | — | 6.0 | 7.4 | 1.8 | — | 2.0 | 2.3 | — | 1.6 | — | 3.2 | 6.1 | — | 3.2 | 1.4 |
| Whooping Cough | — | — | 1.3 | 1.8 | 1.5 | — | — | — | — | 1.4 | — | — | — | 1.6 | 2.8 |
| Diphtheria | — | — | — | — | — | 2.0 | 4.6 | — | — | 1.4 | 1.6 | — | — | 3.2 | 1.4 |
| Catarrh | — | — | 1.3 | — | — | — | — | — | 1.6 | 5.5 | 1.6 | 3.0 | 9.1 | 3.2 | 2.8 |
| Brain Fever | — | — | — | — | 2.9 | — | — | 11.1 | — | — | — | 6.1 | 3.6 | 4.8 | 4.3 |
| Miscellaneous and Unknown | 30.9 | 19.9 | 3.2 | 26.8 | 6.2 | 14.0 | 4.5 | 20.9 | 4.7 | 12.7 | 8.5 | 33.3 | 31.3 | 31.7 | 28.7 |
We may take these tables together to see how the proportions of deafness from the leading diseases have changed in the course of the several periods indicated, proper allowance being made for the shorter length of time covered in some schools than in others. In respect to scarlet fever, one of the two foremost causes, we find in the New York Institution, the Michigan School and the Maryland School, a distinct and steady decline; in the Pennsylvania Institution a decline of late years, which is especially significant in view of the extended period covered by it; and in the Western Pennsylvania and the Wisconsin School little change, though in the latter there is less than at the beginning. In meningitis, on the other hand, the second of the two most important causes, a marked increase is seen in the Pennsylvania Institution for the entire period, while in the New York a sharp increase is found in the time designated, this being all the more noticeable because of the large proportion already attributed here to convulsions, often a trouble of kindred origin. In the Western Pennsylvania Institution and the Maryland School little change is observed, though in the latter some decline is apparent in the later years. In the Wisconsin and Michigan schools a very strong decline is seen. On somewhat the same order as meningitis is brain fever. It, however, shows little change on the whole, though in the Michigan and Maryland schools and the New York Institution some decline is evident. Of the remaining diseases none plays singly a large part in the causation of deafness, and in most of them the results are similar. Measles, typhoid fever, diphtheria, pneumonia, and whooping cough show, with some fluctuations at times, little change on the whole, beyond certain local differences. In the New York Institution a decline is reported in nearly all. In the Pennsylvania Institution a rather larger proportion for measles is seen in later than in earlier years. In the Michigan School an increase seems to be the case with whooping cough, but a decrease with typhoid fever. In catarrh the results are not so uniform. In the New York and Pennsylvania institutions a decline is manifest, though in the latter a larger proportion is reported than at the beginning. In the Michigan and Wisconsin schools rather an increase is noted. La grippe is only reported occasionally of late years, and its real effects cannot yet be ascertained. With respect to general fevers, their classification is found to be so varying that little can be determined.
We now proceed to make comparison of the proportions of deafness from the principal diseases in a series of years some time past with similar proportions in recent years. The following tables give the several proportions in the American School (Connecticut) in the entire attendance from 1817 to 1844 and from 1817 to 1857, and in the new admissions from 1901 to 1913; in the Ohio School in the entire attendance from 1829 to 1872, and in the average annual attendance in 1904, 1905, 1906, and 1911; in the Iowa School in the entire attendance from 1855 to 1870 and from 1855 to 1912; and in the New York Institution in the entire attendance from 1818 to 1853 and in the average annual attendance from 1899 to 1912.[38]
I. CAUSES OF DEAFNESS IN AMERICAN SCHOOL FROM 1817 TO 1844, FROM 1817 TO 1857, AND FROM 1901 TO 1913.
| PERIOD | TOTAL NUMBER | CONGENITAL | SCARLET FEVER | MENINGITIS | TYPHOID FEVER | MEASLES | WHOOPING COUGH | GENERAL FEVERS | BRAIN FEVER | PNEUMONIA | DIPHTHERIA | CATARRH | UNKNOWN AND MIS. |
| 1817‑1844 | 761 | 44.8 | 5.7 | 6.1 | — | 1.6 | 1.6 | 6.7 | — | — | — | — | 33.5 |
| 1817‑1857 | 1081 | 50.1 | 9.2 | 4.6 | — | 1.8 | 1.3 | 5.3 | — | — | — | — | 27.7 |
| 1901‑1913 | 310 | 35.2 | 7.7 | 11.3 | 3.2 | 1.3 | 1.3 | 1.9 | 5.8 | 0.6 | 1.3 | 1.0 | 29.4 |
II. CAUSES OF DEAFNESS IN OHIO SCHOOL FROM 1829 TO 1872 AND FROM 1904 TO 1911.
| PERIOD | TOTAL NUMBER | CONGENITAL | SCARLET FEVER | MENINGITIS | TYPHOID FEVER | MEASLES | WHOOPING COUGH | GENERAL FEVERS | BRAIN FEVER | PNEUMONIA | DIPHTHERIA | CATARRH | UNKNOWN AND MIS. |
| 1829‑1872 | 1252 | 33.8 | 10.3 | 3.0 | 1.8 | 3.2 | 1.7 | 4.6 | 5.7 | — | 0.3 | — | 35.6 |
| 1904‑1911 | — | 38.9 | 5.0 | 9.2 | 1.4 | 2.8 | 1.7 | 1.1 | 5.3 | 0.5 | 0.5 | 3.5 | 30.1 |
III. CAUSES OF DEAFNESS IN IOWA SCHOOL FROM 1855 TO 1870 AND FROM 1855 TO 1912.
| PERIOD | TOTAL NUMBER | CONGENITAL | SCARLET FEVER | MENINGITIS | TYPHOID FEVER | MEASLES | WHOOPING COUGH | GENERAL FEVERS | BRAIN FEVER | PNEUMONIA | DIPHTHERIA | CATARRH | UNKNOWN AND MIS. |
| 1855‑1870 | 245 | 87.2 | 13.4 | 3.3 | 1.6 | 2.0 | 1.3 | 6.1 | 1.3 | — | — | — | 33.8 |
| 1855‑1912 | 1672 | 26.9 | 10.3 | 14.9 | 1.7 | 2.2 | 1.7 | 0.1 | 7.0 | 0.3 | 0.8 | 1.7 | 32.4 |
IV. CAUSES OF DEAFNESS IN NEW YORK INSTITUTION FROM 1818 TO 1853 AND FROM 1899 TO 1912.
| PERIOD | TOTAL NUMBER | CONGENITAL | SCARLET FEVER | MENINGITIS | TYPHOID FEVER | MEASLES | WHOOPING COUGH | GENERAL FEVERS | BRAIN FEVER | PNEUMONIA | DIPHTHERIA | CATARRH | UNKNOWN AND MIS. |
| 1818‑1853 | 1148 | 42.9 | 7.2 | —[39] | — | 1.9 | 0.7 | 1.6 | — | — | — | — | 45.7 |
| 1899‑1912 | — | 38.0 | 6.8 | 13.1 | 1.3 | 3.4 | 0.8 | 1.3 | 8.1 | 0.9 | 0.9 | 1.7 | 23.7 |
Taking these tables also collectively, we find in respect to scarlet fever a decline in all the schools, this being especially pronounced in the case of the Ohio. In meningitis, however, there is an increase so heavy as to call in question the accuracy of the earlier records; and it is possible that it failed to be entirely recognized then. In most of the other diseases, as in the previous case, no very great change is perceptible. In general fevers a decline is apparent in all, in most being considerable; and probably several diseases were formerly included which are now listed separately. In measles rather a decline is found in the American and Ohio schools, but a slight increase in the Iowa, and a somewhat larger one in the New York Institution. In typhoid fever there is a slight increase also in the Iowa School, but a decrease in the Ohio. In brain fever a considerable increase is observed in the Iowa School, but a slight decrease likewise in the Ohio. In whooping cough there is an increase in the New York Institution and the Iowa School, but a decrease in the American. Such diseases as pneumonia, diphtheria and catarrh seem not usually to have been separately classified in the past, though in the Ohio School we find diphtheria noted, and with somewhat smaller proportions than in later years; while in several of the schools we find "colds" given in former times, which may have been in part really catarrh.
Combining now the results of our two groups of tables, we may be able to reach some conclusions with respect to the increase or decrease of deafness from certain diseases, though on the whole far less definite than we could wish. In the first place, it seems safe to affirm that deafness from scarlet fever is becoming relatively less with the years; and it is possible that if it continues its present rate of decline, it will in time cease to be one of the main causes of deafness. On the other hand, meningitis, its great companion in evil, shows a striking increase in comparison with past years, as a cause of adventitious deafness; while its accretion may be traced as well in a series of recent years in certain schools, though not in others. But how far there is an absolute increase in meningitis over the past, and whether it is tending at present actually to increase, may be a matter for question. In view of the possibility that the disease was not sufficiently accounted for in the past, and in the absence of any knowledge to indicate a reason for its less prevalence in earlier years, at least not to the extent indicated by the statistics, it may be that its increase is, after all, more apparent than real. The fact, moreover, that in the series of recent years a marked increase is found in some schools, but a marked decline in others, may perhaps be taken to mean that at present meningitis may be on the increase only in certain sections, depending possibly on local conditions. With the greater medical skill of to-day, and with a larger proportion of children in the schools, it may be open to considerable doubt if the movement of this disease is really one of increase, though it seems that we are on the whole making no great headway against it.
As to the minor diseases causing deafness, our statistics do not indicate just to what extent and in what direction deafness from them is being affected, and no precise conclusions can at present be set down. It is probable, however, that with the increased attention to children's diseases, as we have noted, there is really less deafness from most of them than formerly.[40]
The Congenitally Deaf
When we come to consider the question of congenital deafness, which comprises a little over a third of the total amount of deafness, we have an even more difficult problem on our hands, for here we are to deal with some of the great questions of heredity—though hereditary deafness and congenital deafness are not altogether one and the same thing.[41] For the purposes of our inquiry, let us think of the congenitally deaf as divided into three great classes in respect to their family relations: 1. the offspring of parents who were cousins; 2. the offspring of parents who were themselves deaf or members of families in which there are other deaf relatives; and 3. the product of families without either consanguinity or antecedent deafness. Of these three classes the first two only will engage our attention. Of the last, comprising, according to the census, nine-twentieths, or 44.4 per cent, of the congenitally deaf, there is not much that we can say. For a great part of it there no doubt exists in the parent, or perhaps in a more remote ancestor, some abnormal strain, physical or mental, in the nature of disease or other defect. But in respect to such deafness we have too little in the way of statistical data to help us arrive at any real determination; and for it as a whole we shall have to wait till we have greater knowledge of eugenics and the laws of heredity.[42]
The Offspring of Consanguineous Marriages
Not all the deaf born of consanguineous marriages are congenitally deaf, but as the majority are so, and as the fact of the parents being blood relatives is assumed to have at least a contributing influence in the result, we may consider the matter in this place. It is in fact closely connected with the question of deaf relatives in general.
In the census investigations,[43] of the number who answered on this point, 2,525, or 7.4 per cent, have parents who were cousins. Of these cases, deafness occurred in 87 per cent before the fifth year of age, and in 60 per cent at birth. Of all the deaf born without hearing, 13.5 per cent are the offspring of consanguineous marriages. The proportion of those born deaf is thus nearly twice as great when the parents are cousins as it is among the whole class of the congenitally deaf; and the proportion is also nearly twice as great of the offspring of consanguineous marriages among the congenitally deaf as the proportion of the deaf from such marriages among the total number of the deaf. Moreover, 55.0 per cent of the offspring of cousin-marriages have deaf relatives of some kind, and of the congenitally deaf from cousin-marriages, 65.6 per cent have deaf relatives; while the respective proportions when the parents are not cousins are 25.5 per cent and 40.7 per cent—in the one case less than half, and in the other two-thirds, as great.
Further statistics bear out the findings of the census. Dr. E. A. Fay in his "Marriages of the Deaf"[44]—a work we are soon to notice—finds that, though consanguineous marriages form only about one per cent of the total number considered, 30.0 per cent of the children of deaf parents who are cousins are deaf, and that 45.1 per cent of such marriages result in deaf offspring; but that when the parents are not cousins, the respective proportions are 8.3 per cent and 9.3 per cent—only about a fourth and a fifth as great. In the Colorado School, out of 567 pupils in attendance from the beginning to 1912, in 17, or 3 per cent, the parents were related before marriage. In the Kentucky School, out of 83 pupils admitted in 1910 and 1911, 18, or 19.3 per cent, and out of 42 admitted in 1912 and 1913, 8, or 19 per cent, were the offspring of parents who were cousins. In the Iowa School, out of 62 admissions in 1911 and 1912, 4, or 6.5 per cent, and in the Maryland School, out of a total attendance in 1911 of 135, 13, or 9.2 per cent, had parents who were cousins.[45]
Consanguineous marriages, so far as the effect on deafness is concerned, are not of relatively frequent occurrence. But where they do take place, there is found a decided connection between them and deafness, the increased tendency thus to transmit a physical abnormality being plain. How far, however, if at all, such deafness is to be directly ascribed to consanguineous marriages, is a matter for question. The main consideration seems to be that in such marriages the chances are at least doubled of the offspring acquiring the characteristics of the parents; and that in them the liability is thus proportionately enhanced of transmitting deafness.[46]
The Deaf Having Deaf Relatives
We are now to examine what traces there may be of deafness in a family by noting what proportion of the deaf have deaf relatives, and are to attempt to see what may be its bearings upon the question of heredity. In the census investigations,[47] we find that out of 34,780 deaf persons who answered, there are 10,033, or 28.8 per cent, who have deaf relatives of some kind, direct or collateral, 8,170, or 23.5 per cent, having deaf brothers, sisters or ancestors. In all of these we can without difficulty discover the influence of heredity. In the congenitally deaf the trace of a physical defect is even more clearly indicated. Of these 40.1 per cent have deaf brothers, sisters or ancestors, and 46.2 per cent have also deaf uncles, cousins, etc.[48]
It is thus evident that there are certain families in society deeply tinged with deafness, that it sometimes passes from parent to child, from generation to generation, and that like a cloud it hangs over a section of the race.
The Offspring of Deaf Parents
All this argument leads up to one most pertinent question: Are the statistics which we have indicative that this deafness which passes so remorselessly in certain families will be found all the stronger in the children of deaf parents? Have we ground to believe or fear that this deafness will crop out far more surely than in the children of parents not deaf? And can we determine to what extent possibilities are increased of the offspring of deaf parents being likewise deaf?
Let us now consider the statistics which we have in this matter, first examining the results of the census investigation.[49] Of the 8,022 married deaf persons for whom statements are made, we find that there are 190 who have deaf offspring, or 2.4 per cent. Of the 4,116 deaf persons who are married to deaf persons, 137 have deaf children, or 3.3 per cent; and of the 3,906 deaf persons married to hearing persons, 53 have deaf children, or 1.4 per cent. Of the married deaf having deaf children, 52.5 per cent have deaf relatives of some kind, and 54.7 per cent are congenitally deaf, the proportion of those having deaf relatives who are also congenitally deaf being 66.7 per cent. Of the deaf married to hearing partners, who have deaf children, 26.4 per cent are congenitally deaf, while 50.9 per cent of the partners in such marriages have deaf relatives of some kind.
From the census statistics, then, it appears that the married deaf as a class do not have a large proportion of deaf children, and that this proportion is only a little more than twice as great when the deaf are married to the deaf as when they are married to the hearing. It appears also, however, that when there are deaf relatives involved in either kind of marriages, or when there is congenital deafness in the deaf parent, the effect is quite marked in the offspring.
Besides the census returns, we have the statistics presented in the reports of certain schools, which are found to point, as far as they go, to the same conclusions. In the Kentucky School, out of 83 pupils admitted in 1910 and 1911, there were none the children of deaf parents, though 35, or 30.1 per cent, had deaf relatives; and out of 42 admitted in 1912 and 1913, there were 2, or 4.8 per cent, the children of deaf parents, and 12, or 28.8 per cent, with deaf relatives. In the Iowa School, out of 62 admissions in 1911 and 1912, 4, or 6.5 per cent, had deaf parents, and 21, or 33.9 per cent, "defective" relatives. In the Michigan School, with an annual enrollment of some three hundred, there were from 1903 to 1908 but three children of deaf parents.[50] In the Colorado School, out of a total attendance since its founding to 1912 of 567, 3, or 0.57 per cent, were the children of deaf parents, though 83, or 14.6 per cent, had deaf relatives. In the Missouri School, out of a similar attendance to 1912 of 2,174 there were 52, or 2.4 per cent, with deaf parents, though there were 235, or 10.8 per cent, with deaf relatives.[51]
The most exhaustive study of the question of the liability of the deaf to deaf offspring is that of Dr. E. A. Fay in his "Marriages of the Deaf"—covering the majority of the marriages of the deaf in America at the time it was made (1898).[52] Statistical information is presented for 7,227 deaf persons and for 3,078 marriages with either deaf or hearing partners.[53] In the following table are summarized the results of this investigation.[54]
MARRIAGES OF DEAF PERSONS
| NUMBER OF MARRIAGES | NUMBER OF CHILDREN | |||||
| Partners in Marriage | Total | Resulting in deaf children | Per cent | Total | Deaf | Per cent |
| One or both deaf | 3,078 | 300 | 9.7 | 6,782 | 588 | 8.6 |
| Both deaf | 2,377 | 220 | 9.2 | 5,072 | 429 | 8.4 |
| One deaf, other hearing | 599 | 75 | 12.5 | 1,532 | 151 | 9.8 |
| One or both congenitally deaf | 1,477 | 194 | 13.1 | 3,401 | 413 | 12.1 |
| One or both adventitiously deaf | 2,212 | 124 | 5.6 | 4,701 | 199 | 4.2 |
| Both congenitally deaf | 335 | 83 | 24.7 | 779 | 202 | 25.9 |
| One congenitally, other adventitiously deaf | 814 | 66 | 8.1 | 1,820 | 119 | 6.5 |
| Both adventitiously deaf | 845 | 30 | 3.5 | 1,720 | 40 | 2.3 |
| One congenitally deaf, other hearing | 191 | 28 | 14.6 | 528 | 63 | 11.9 |
| One adventitiously deaf, other hearing | 310 | 10 | 3.2 | 713 | 16 | 2.2 |
| Both had deaf relatives | 437 | 103 | 23.5 | 1,060 | 222 | 20.9 |
| One had deaf relatives, other not | 541 | 36 | 6.6 | 1,210 | 78 | 6.4 |
| Neither had deaf relatives | 471 | 11 | 2.3 | 1,044 | 13 | 1.2 |
| Both congenitally deaf | ||||||
| Both had deaf relatives | 172 | 49 | 28.4 | 429 | 130 | 30.3 |
| One had deaf relatives, other not | 49 | 8 | 16.3 | 105 | 21 | 20.0 |
| Neither had deaf relatives | 14 | 1 | 7.1 | 24 | 1 | 4.1 |
| Both adventitiously deaf | ||||||
| Both had deaf relatives | 57 | 10 | 17.5 | 114 | 11 | 9.6 |
| One had deaf relatives, other not | 167 | 7 | 4.1 | 357 | 10 | 2.8 |
| Neither had deaf relatives | 284 | 2 | 0.7 | 550 | 2 | 0.3 |
| Partners consanguineous | 31 | 14 | 45.1 | 100 | 30 | 30.0 |
It is thus seen that 9.7 per cent of the marriages of the deaf result in deaf offspring, and that 8.6 per cent of the children born of them are deaf—proportions far greater than for the the population generally.[55] A striking fact to be noted, however, is that these proportions are greater when one parent is deaf and the other hearing than when both are deaf. The percentage of marriages resulting in deaf offspring when only one parent is deaf is 12.5, and when both are deaf, 9.2; while the percentage of deaf children born of them when only one parent is deaf is 9.8, and when both are deaf, 8.4. This is apparently a very strange result, though it probably may be accounted for in some part on the theory that it is not so much deafness itself that is inherited, but rather an abnormality of the auditory organs, or a tendency to disease, of which deafness is a result or symptom, and that with different pathological conditions in the parent there is less likelihood of deafness resulting.
The most significant part of the results seems to be found, as before, in respect to whether or not deaf parents are themselves congenitally deaf or have deaf relatives. On the one hand, when one or both of the parents are adventitiously deaf, the percentage of marriages resulting in deaf children is 5.6, and the percentage of deaf children is 4.2; when both parents are so, the percentages are lower: 3.5 and 2.3. The percentages rise when one parent is adventitiously deaf, and the other congenitally: 8.1 and 6.5. In respect to deaf relatives of parents, the percentages are very low when neither has such relatives: 2.3 and 1.2. The lowest percentages of all are in the case where both parents are adventitiously deaf and neither has deaf relatives: 0.7 and 0.3.
On the other hand, we find the proportion of marriages resulting in deaf offspring and the proportion of deaf children much greater when there is congenital deafness in one or both parents, when one or both have deaf relatives, and greatest of all when these influences are combined. When one or both parents are congenitally deaf, the percentage of marriages resulting in deaf offspring is 13.1, and the percentage of deaf children is 12.1; when both parents are so, the percentages are doubled: 24.7 and 25.9. When one parent has deaf relatives and the other has not, the percentages are 6.6 and 6.4; when both have, the percentages are nearly four times as great: 23.5 and 20.9. When both parents are congenitally deaf but neither has deaf relatives, the percentages are 7.1 and 4.1. When both are adventitiously deaf and both have deaf relatives, the percentages are 17.5 and 9.6. When both are congenitally deaf and one has deaf relatives, the percentages are 16.3 and 20.0; and when both have deaf relatives, the percentages are 28.4 and 30.3.
The evidence is very strong, then, with regard to the form of deafness and the presence or absence of deaf relatives. In cases where the parents are not congenitally deaf and have no deaf relatives, the proportion of deaf children is very low. When one or both parents are congenitally deaf or have deaf relatives—when the deafness is inherited or in the family—the likelihood becomes far greater, and greater still when the two influences are in conjunction. In general, in respect to the influences of heredity upon deafness, the main determinants seem to be found in the existence in the parties, whether hearing or deaf, of deaf relatives, and, to a less extent, in the existence in parties who are deaf of congenital deafness.
Possible Action for the Prevention of Congenital Deafness
We come now to the consideration of the question of possible action for the prevention of congenital deafness. This examination naturally centers about the matter of the regulation of marriage, with due attention to the extent that action on the part of the state is to be regarded as desirable or feasible.
We have seen that congenital deafness may, hypothetically, be divided into three distinguishable classes: that in which consanguineous marriages are concerned, that in which there is antecedent deafness in the family, and that in which neither of these conditions occurs; and in our inquiry it has seemed best to take up each of these separately. It may be, however, that there is in fact no very radical difference between these several forms, and that with increased knowledge on the subject a more or less intimate relation will be found to exist.
Of that form of deafness in which neither consanguineous marriages nor antecedent deafness is involved, we are at present, as we have noted, able to say little definitely. In most cases we may be convinced that there exists in the parent some peculiar state of morbidity or other affection, latent or manifest, perhaps to some extent of hereditary influence, which has an effect on the organs of hearing of the offspring. A certain proportion is quite possibly due to recognizable defects both of physical and mental character. Our statistical evidence, however, in respect to this form of congenital deafness is too slight to warrant any positive deductions; and we will have to wait for further investigation to determine its nature fully. None the less, marriage of persons known to be liable to have ill effect on possible offspring is objectionable for not a few reasons, from the standpoint of the interests of society; and in their reduction there will probably be a greater or less diminution of congenital deafness.
With regard to consanguineous marriages and their effect on deafness we are on surer ground, so far as may be indicated by statistical data. This question is found in very great measure to be connected with that of deaf relatives in general. The matter appears to be largely a part of a law of wide application, namely, that in the blood relationship of parents the possibilities are intensified of the perpetuation of a certain strain, which holds true no less with the transmission of deafness. Consanguineous marriages are perhaps not of sufficiently frequent occurrence, so far as concerns the effect on deafness, to require special action; but in the consideration of such marriages in general, their part in the causation of deafness should have due weight; and whatever may be said regarding them in other relations, they are to be avoided if we wish to remove all chances of this kind of deafness resulting.
The problem of deaf relatives and their connection with congenital deafness is a very large one. Attention however, has mostly been focused upon it in relation to the intermarriage of the deaf and its effect upon their offspring. Indeed, in such unions there has already been more or less concern, and there has even been question whether it is a wise or unwise policy to allow the deaf to marry other deaf persons. The deaf, as we shall discover, not only find their companions for social intercourse among similar deaf persons, but a fortiori very often seek such persons for their partners in marriage—in fact, more often than they do hearing partners, nearly three-fourths of the married deaf being married to deaf partners.[56] Not only has it been feared that the offspring of such marriages might likewise be deaf, but there has also been apprehension lest in their encouragement there might result a deaf species of the race.[57]
From our discussion, however, we have found that in most of the marriages of the deaf we have but small reason for disquiet. If deafness in the parent is really adventitious, there is little possibility of its passing on to the offspring. When the deafness in the parent is itself congenital, the situation becomes more serious. If in such case there is no added risk from the existence of deaf relatives, the likelihood of transmitting deafness need not always be a matter of deep concern, though the hazard is materially larger than for adventitious deafness. When there are deaf relatives involved, the peril, made stronger if coupled with congenital deafness, is most pronounced; and, indeed, the existence of collateral deafness seems a more certain sign of warning than direct heredity itself. Finally, even in the marriage of the deaf with the hearing, the dangers are not in fact lessened if conditions otherwise unchanged are attendant.
What action should be taken in respect to that part of the deaf who may marry under conditions favorable to the production of deaf offspring is not at present clear. Legislation would not appear on the whole to be advisable;[58] and the exertion of moral suasion, so far as possible, in the individual cases concerned would seem a more acceptable course. The matter, however, really belongs in the province of eugenics, and we will probably do best to await the authoritative pronouncement of its decrees before full procedure is resolved upon.
Congenital Deafness as an Increasing or Decreasing Phenomenon
The final matter to be ascertained in respect to congenital deafness is whether it is relatively increasing or decreasing. The following table will show the number of the congenitally deaf in the censuses of 1880, 1890, and 1900, with their respective percentages and the ratios per million of population.[59]
NUMBER OF THE CONGENITALLY DEAF IN 1880, 1890, AND 1900
| Total Number | Congenitally Deaf | Per Cent | Ratio per Million of Population | |
| 1880 | 33,878 | 12,155 | 35.6 | 242 |
| 1890 | 40,562 | 16,866 | 41.2 | 269 |
| 1900 | 37,426 | 12,609 | 33.7 | 166 |
From this it appears that congenital deafness is decreasing both in relation to all deafness, and to the general population.
For further statistics, we may revert to our tables under adventitious deafness. In the tables relating to periods of successive recent years we find in respect to three schools, the New York and Western Pennsylvania institutions and the Maryland School, with certain fluctuations, no great change on the whole, though the last named school shows still a very high proportion. In two schools, the Michigan and Wisconsin, rather an increase is observed. In the Pennsylvania Institution, which covers a period of seventy years, there is a decrease from over 50 per cent to less than 40.
A better test perhaps lies in the comparison of the proportions found for congenital deafness in the tables relating to periods widely separated in time. In these an increase is seen in the single case of the Ohio School; while a decrease is apparent in three, namely, the American and Iowa schools and the New York Institution. These decreases in percentages are respectively from 44.8 and 50.1 to 35.2; from 37.2 to 26.9; and from 42.9 to 38.0.[60]
From the evidence that we have, then, taken together, it seems reasonable to conclude that congenital deafness is, though slowly, becoming less in the course of the years.
Conclusions with Respect to the Elimination or Prevention of Deafness
Most of what has been said in this chapter with respect to the elimination or prevention of deafness may be summed up as follows:
1. There are two kinds of deafness—adventitious and congenital. Of the total number of cases adventitious deafness comprises nearly two-thirds, and congenital deafness a little over one-third.
2. Nearly all adventitious deafness is caused by some disease of infancy or childhood attacking the middle or internal ear, a large part being of infectious character. The two chief diseases causing such deafness are scarlet fever and meningitis, with a less amount from brain fever, typhoid fever, measles, catarrh, diphtheria, whooping cough, etc.
3. A considerable part of this deafness is preventable under enlightened action. Medical science is principally in control of the situation, but there is also much that can be done in general measures for the protection of the health. In attacking the problem, the most immediate practical program lies in the arrest of those diseases, especially infantile and infectious diseases, that cause deafness.
4. Our evidence is incomplete to determine definitely whether adventitious deafness is increasing or decreasing relatively among the population; but it is hardly other than likely that it is decreasing. Although certain diseases producing deafness fail to show any extensive signs of abatement, there are other diseases from which there can be little doubt that deafness is decreasing.
5. In the outlook there is, on the whole, promise, both in respect to the treatment of deafness itself and of the diseases that lead to deafness, though it cannot be said in any sense that any large or general relief is at present in sight.
6. Of congenital deafness nearly half occurs in families often without any positively known strain to indicate a predisposition to deafness. Though concerning this deafness little in the present state of our knowledge can be predicated, it is likely that with measures to secure a race sound in all particulars there will be a reduction to a greater or less extent of such deafness.
7. Consanguineous marriages do not take place, so far as deafness as an effect is concerned, to any great extent; though where they do the consequences are very marked. Their relation to deafness consists apparently for the greatest part in the fact that the chances of its transmission are thereby intensified, there being also a very strong connection with the question of deaf relatives in general.
8. There are a certain number of families in society deeply tainted with deafness, in evidence both lineally and collaterally, and this deafness may be transmitted from parent to offspring.
9. Children of deaf parents are far more likely to be deaf than children of hearing parents.
10. The great majority of the children of deaf parents, however, are able to hear, the proportion of those who are not being small.
11. The likelihood of deaf offspring is not necessarily greater when both parents are deaf than when one is deaf and the other hearing.
12. The liability to deaf offspring depends in the greatest degree upon the presence or absence in the parents, deaf or hearing, of deaf relatives, and, to a less extent, upon whether or not the existing deafness is congenital—being especially great under a combination of these two conditions.
13. Action in respect to marriages of the deaf likely to result in deaf offspring seems for the present rather to be limited to moral forces.
14. Congenital deafness appears, from all the evidence, to be decreasing relatively among the population, though probably only at a very slow rate.
15. Finally, with respect to our original inquiry, it is to be said that there are no indications that deafness will disappear from the human race within any time which we can measure; and hence that the deaf are to be in society not only for a season, but for a period apparently as yet indefinite. Nevertheless the situation is not without encouragement. From the data in our possession regarding deafness as a whole, it seems certain that deafness is not on the increase relatively among the population. From our knowledge concerning adventitious deafness, the probabilities are that, if anything, it is decreasing; while the evidence as to congenital deafness is that it is decreasing. It is likely, then, that deafness in general is tending to decrease; and we are thus justified in believing that the number of the deaf will in time become less.