(c) The Larval or Abortive Form.—Toward the close of an epidemic the character of the disease usually undergoes a change. It becomes less malignant. The cases present the essential symptoms, but in diminished intensity. Some cases terminate in an early defervescence with rapid subsidence of beginning local manifestations; others present merely the evidences of a slight disturbance of the general health, without any characteristic symptoms of the prevalent disorder; others, again, are characterized by the appearance of buboes without pain or fever. These swellings undergo resolution in fourteen days or thereabout. Exceptionally they suppurate.
The duration of the plague is from six to ten days in typical cases running a favorable course; those of fatal cases from one to twenty days. Clot Bey8 found the duration of the worst cases two or three days, of those next in point of severity five or six days, whilst in milder cases death did not occur until the second or third week. Of 534 fatal cases noted by W. H. Colvill, 126 occurred one day after the attack, 80 two days after it, 105 three days, 76 four days, 60 five days, 26 six days after the attack. After six days the number of deaths rapidly declined; on the nineteenth day 1 death, and on the twentieth day after the attack 11 deaths, occurred. It is said that death after the seventh day is commonly not in consequence of the disease itself, but of sequels. Of 16 fatal cases in the village Prischib in Astrakhan, noted in the report of Dr. Cabiadis, and of whom the names, as well as the day of their exposure, their falling sick, and their death are given, 1 died in one day, 4 in two days, 6 in three days, 3 in four days, and 2 in six days.
8 De la Peste observée en Égypte, Paris, 1840.
The mortality of the plague is greater than that of any other epidemic disease. In all epidemics a large majority of those who contract the disease die. This is especially true of epidemics at their beginning, when it has often happened that for a time all the cases have perished. Of this, as of other epidemic diseases, it is true that the death-rate has varied in different outbreaks and at different periods of the same outbreak. Colvill states that in the epidemic of 1874 in Mesopotamia the mortality of stricken villages during the first half of the time was 93 to 95 per cent. of those attacked, but that afterward the majority of those attacked recovered. The same authority states that in Bagdad in 1876 the mortality was 55.7 per cent. of persons attacked. Arnauld gives the mortality at Benghazi in 1874 as 39 per cent. of attacks. The death-rate at Vetlanka was 82 per cent. of those attacked. In Toulon in 1721, of a population of about 26,000 human beings, about 20,000 were attacked, and of these 16,000 died. It has been by no means of rare occurrence that nearly half the population of towns have perished in an epidemic, or that small villages have been completely depopulated by this scourge.
COMPLICATIONS AND SEQUELS.—The appalling mortality of the plague on its approach, the rapidity of its spread, the popular commotion upon its appearance, its brief course, and the fact that its recent outbreaks have taken place in regions where trained European physicians have been, with a few exceptions, beyond reach, all unite in maintaining the gloom that has since the Middle Ages enveloped the clinical facts of this disease.
Of its clinical course, beyond the brief outline already given, little is accurately known, of its complications still less. In some of the recent epidemics, and particularly in the outbreaks of plague in India, the evidences of pulmonary lesions have been so conspicuous that they deserve to be classed among the essential manifestations of the disease rather than as complications; in others pulmonary congestion, hæmoptysis, the evidences of croupous or catarrhal pneumonia, have occurred in a small proportion of the cases. Aside from this, there is nothing to be said as to the complications.
Among the known sequels are protracted ulceration of the enlarged lymphatics, boils, superficial or deep abscesses, catarrhal pneumonia, pertussis, mental troubles, and the like. Extensive and deep cicatrices are not infrequently found in the site of the ulcerating local manifestations.
MORBID ANATOMY.—The existing knowledge of the morbid anatomy of the plague is but scanty. The observers of the early outbreaks contributed nothing; the recent outbreaks have taken place under circumstances in which anatomical investigations were impracticable. The knowledge which we possess is almost wholly due to the investigations conducted by the French in Egypt at the close of the last and the beginning of the present century, and again during the years 1833 to 1838.
The descriptions of Bulant,9 Clot Bey, and others point to gross lesions, such as are found after death in the acute stages of the infectious diseases in general. The viscera were engorged with dark fluid blood; ecchymoses were often found in the mucous and the serous membranes, in the substance of the different organs, and into the connective tissue. The spleen was in almost all cases enlarged, softened, and of a dark color. Not rarely the kidneys were deeply engorged, and extravasations of blood into their substance, their pelves, and into the surrounding connective tissues were often encountered.
9 De la peste oriental d'apres les matérnaux recuillés à Alexandrie, à Smyrne, etc., pendant les Années 1833 à 1838, Paris, 1839.