Marriages of the Deaf. Number of
Marriages.		 Number of
Children.		 Percentage.
Total. Resulting
in deaf
offspring. 		Total. Deaf. Marriages
resulting
in deaf
offspring. 		Deaf
children.
One or both partners deaf 3078 300 6782 588 9.7 8.6
Both partners deaf 2377 220 5072 429 9.2 8.4
One partner deaf, the other hearing 599 75 1532 151 12.5 9.8
One or both partners congenitally deaf 1477 194 3401 413 13.1 12.1
One or both partners adventitiously deaf 2212 124 4701 199 5.6 4.2
Both partners congenitally deaf 335 83 779 202 24.7 25.9
One partner congenitally deaf, the other adventitiously deaf 814 66 1820 119 8.1 6.5
Both partners adventitiously deaf 845 30 1720 40 3.5 2.3
One partner congenitally deaf, the other hearing 191 28 528 63 14.6 11.9
One partner adventitiously deaf, the other hearing 310 10 713 16 3.2 2.2
Both partners had deaf relatives 437 103 1060 222 23.5 20.9
One partner had deaf relatives, the other had not 541 36 1210 78 6.6 6.4
Neither partner had deaf relatives 471 11 1044 13 2.3 1.2
Both partners congenitally deaf; both had deaf relatives 172 49 429 130 28.4 30.3
Both partners congenitally deaf; one had deaf relatives, the other had not 49 8 105 21 16.3 20.0
Both partners congenitally deaf; neither had deaf relatives 14 1 24 1 7.1 4.1
Both partners adventitiously deaf; both had deaf relatives 57 10 114 11 17.5 9.6
Both partners adventitiously deaf; one had deaf relatives, the other had not 167 7 357 10 4.1 2.8
Both partners adventitiously deaf; neither had deaf relatives 284 2 550 2 0.7 0.3
Partners consanguineous 31 14 100 30 45.1 30.0

One point deserves special attention in the above list. It is that where there are no deaf relatives (i.e. where there has not been a history of deafness in the family) only one child out of twenty-four is deaf, even when the parents were both born deaf themselves. Where there were deaf relatives already in the family on both sides, and the parents were born deaf, the percentage of deaf children is seven and a half times as great. This seems to show that there are causes of congenital deafness which are, comparatively speaking, unlikely to be transmitted to future generations, while other causes of congenital deafness are so liable to be perpetuated that one child in every three is deaf. We conjecture that one original cause of congenital deafness which reappears in a family is consanguinity—for instance, the intermarriage of first or second cousins (hearing people) in some previous generation. Out of the 2245 deaf persons who were born deaf, 269 had parents who were blood relations, according to Fay. And perhaps many more refrained from acknowledging the fact. Eleven had grandparents who were cousins. This theory calls for investigation, and while the marriage of deaf people is not encouraged, it is fair to ask those who so strenuously oppose such unions whether they may not be spending their energies on trying to check an effect instead of a cause, and if that cause may not really be consanguinity,—witness the percentage of deaf people among Roman Catholics, Protestants and Jews before noticed. On the principle that prevention is better than cure it is the intermarriage of cousins and other relations which should be discouraged. The marriage of deaf people is inadvisable where there has been deafness in the family in former generations, but the same warning applies to all the other members of that family, for the hearing members are as likely to transmit the defect of which deafness is a symptom as the deaf members are. We are more concerned to discover the primary cause of the defect, and take steps to prevent the latter from occurring at all. Those who have no dissuasions for hearing people, who might perhaps cause the misery, and only give counsel to those among the transmitters of it who happen to be deaf, are acting in a manner which is hardly logical.

2. Post-Natal.—We have collected and grouped the stated causes of deafness in those partners of the marriages in America noticed by Fay. About a hundred and thirty did not mention how they lost hearing. Any errors in this calculation must be less than 1% at most, and can make no material difference. In some cases two or more diseases are given as the cause of deafness. In such cases where one is a very common cause of deafness, and the other is unusual, the former is credited with being the reason for the defect. Where both are common, we have divided the cases between them in a rough proportion.

Scarlet fever 973; scarlatina 3; scarlet rash 2978
Spotted fever 260; meningitis 92; spinal meningitis 76;
   cerebro-spinal meningitis 70; spinal fever 28; spinal
   disease 8; congestion of spine 2		536
Brain fever 309; inflammation of brain 62; congestion of brain
   30; disease in brain 3		404
Typhoid 127; “fever” (unspecified) 117; typhus 17; intermittent
   fever 14; bilious fever 11; other fevers 14		300
Gatherings, inflammations, in head; ulcers, disease, sores,
   risings, &c., all but 22 being explicitly stated to be in
   head or ears		276
“Sickness” 167; “illness” 49; “disease” 8; no definite
   specification 12		236
Measles191
Colds 101; colds in head, &c. 35; catarrh 19; catarrhal fevers
   10; chills, &c. 17		182
Whooping cough 77; diphtheria 34; lung fever, and various
   diseases of lungs and throat 60		171
Falls143
Fits and convulsions 58; spasms 18; teething 1692
Scrofula 35; mumps 25; swellings on neck 262
Many various and unusual causes60
Smallpox 8; chickenpox 6, cholera, &c. 7; canker, &c. 11;
   erysipelas 13		45
Paralysis, &c. 12; nerve diseases 12; fright 8; palsy 335
Hydrocephalus 14; dropsy on brain or in head 17; dropsy 233
Various accidents, blows, kicks, &c.31
Quinine 22; other medicines 729
——
Total3804
——

We have counted a hundred and thirty of those who were returned as having lost hearing who were also stated to be the offspring of consanguineous marriages.

Dr Kerr Love (Deaf Mutism, p. 150) gives the following list compiled from the registers of British institutions:—

Scarlet fever331
Miscellaneous causes175
Teething, convulsions, &c.171
Meningitis, brain fever, &c.166
Measles138
Falls and accidents122
Enteric and other fevers119
Disease, illness, &c.37
Whooping cough33
Suppurative ear diseases18
Syphilis2
——
1312
Unknown causes98

The same writer quotes Hartmann’s table, compiled in 1880 from continental statistics, as follows:—

Cerebral affections, inflammations, convulsions644
Cerebro-spinal meningitis295
Typhus260
Scarlatina205
Measles84
Ear disease, proper77
Lesions of the head70
Other diseases354
——
1989