16 In the U. S. Sanitary Commission Memoirs, Russel reports: "The surgeons on duty with the regiments in the barracks (Benton, Mo., 1864) report that men occupying the same bunks with those affected were very much more liable to be attacked than those more remote. Some of the most intelligent surgeons were led to believe that the disease was actually contagious."
During the winter of 1881–82 I remember three instances where two individuals in the same house were simultaneously attacked with croupous pneumonia.
Pythogenic pneumonia is a form which arises under miasmatic influences, and is contagious.17
17 Dub. Med. Journal, 1874, vol. i., Grimshaw and Moore.
"The epidemic form of croupous pneumonia at certain times bears the distinct characteristics of a specific infectious disease."18 Miasmatic and zymotic pneumonia are names which have also been given to this form; and indeed it is now generally acknowledged that croupous pneumonia does occur as an epidemic disease when it is, seemingly, dependent upon a specific contagion. Huss thinks that during a typhus epidemic pneumonia is apt to assume the low typhoid form.
18 Berliner klinische Wochensch., 1879, No. 37, A. Kühn.
Moreover, as in typhoid and cerebro-spinal meningitis, so in pneumonia, we have abortive cases, and forms which are distinguished by the names sthenic, asthenic, malignant typhoid, icteric, etc. Still, a pneumonia epidemic is different from a typhoid or cholera epidemic: it does not sweep over large districts and affect all ages and classes indiscriminately.
Every acute general disease has its complications, and the occurrence in pneumonia of peri- and endocarditis, as well as its cerebral and renal complications, allies it to other acute general diseases.
Cerebro-spinal fever has its characteristic lesion in the membranes at the base of the brain and about the cord; typhoid fever, in the lymph-structures of the intestinal tract; diphtheria commences in and chiefly involves the epithelia; and pneumonia has its characteristic local lesions in the vesicular structure of the lungs. Croupous pneumonia is occasionally met with in intrauterine life, and it is to be remembered that acute general diseases occur far oftener in the foetus than local inflammations. Again, the accepted treatment of pneumonia at the present day is an indication of its specific character. Thus the weight of evidence leads to the opinion that pneumonia is an acute specific general disease caused by a specific poison. The nature and action of the pneumonia-poison may be indicated by the following facts and experiments: Hyperinosis does not seem capable of causing croupous pneumonia; the fibrin increases as the consolidation is completed, and does not antedate either the pyrexia or the hepatization. Excessive bleeding increases the amount of fibrin obtainable from the blood; and when, in pneumonia, we find one lung weighing three pounds more than the other, may not the blood-elements effused into the alveoli have much to do with the hyperinosis?
Pneumonia resembles quinsy19 in its pyrexia, temperature-curves, duration, its constitutional as compared with its local symptoms, and its rapid and abrupt decline. Both have a similar herpetic eruption, and in both the amount of chlorides in the urine is subnormal, the urea (in both) being increased.