ANNUAL REPORT BROOKLYN HEALTH DEPARTMENT. 
157 
There are, sir, about 5,000 head of milch cows contained in 
about 450 stables, within and just outside the limits of this city. 
Ten per cent, of the former are affected in one or other of the 
various stages of this disease, and at least eighty per cent, of the 
stables are of themselves permanent centers of contagion, and 
that beyond the control of disinfectants. 
The experience of foreign countries, and the recent investiga¬ 
tions of so-called contagious pleuro-pneumonia, as well as other 
contagious bovine diseases, have fortified the hands of sanita¬ 
rians in their efforts to control their spread, and have enabled 
them to view their importance and aetiology in a clearer light. 
I consider that the term contagious pleuro-pneumonia, in its 
application to this disease, is a misnomer, and that its character 
would be more intelligently comprehended in defining it as a 
zymotic bovine lung-fever, the fever being the disease and the 
pulmonary complications the sympathetic features. In my 
opinion, there are three distinct periods in its progress—viz: the 
latent, incubative, and special appointing—and by giving due 
consideration to these three stages, you can better comprehend 
the necessity of careful measures in effectually dealing with this 
pest. During the first of these stages, as the name implies, the 
germ may be lying latent in the system, and this for an indefinite 
period, ranging from four days to four months, during which 
the most critical examination will fail to detect in the animal 
anything abnormal. The second or incubative period is charac¬ 
terized by the presence of general febrile symptoms, while the 
third stage exhibits the pathognomonic pulmonary lesions. That 
due weight has not been given to the often protracted first or 
latent period, and to the tenacious vitality of its germ, must be 
ascribed the non-success of many of the efforts hitherto in vogue, 
while attempting to eradicate the disease both here and in other 
countries. 
As to remedial measures. Experience has taught us that there 
are but two courses which can be taken in meeting or controlling 
this scourge—viz : the slaughtering process, and that of inocula¬ 
tion—and the relative merits of these different measures, in their 
applicability to Brooklyn, can be briefly stated as follows : 
Taking the latent period of the disease into consideration, it 
