537 
ceptional conditions. All the photographs are those of animals that 
were among a total of about 50 tuberculous cattle received at the ex- 
periment station during the last three years, and among this total of 
' 50 there were at least 25 animals that could well have been used to 
illustrate the excellent physical condition of dangerously tuberculous 
I cattle and about 40 that could have been used to illustrate simply the 
I healthy, normal appearance of tuberculous cows. 
As all persons are not acquainted with the miserable appearance of 
I the cows from which a large part of the public milk supply is de- 
rived, and as it will serve as a means to emphasize by comparison the 
frequently excellent condition of seemingly healthy but, in fact, dan- 
I gerously tuberculous cattle, two pictures are presented which show by 
j no means the thinnest and most objectionable kind of cows actually 
found in dairy herds. 
HOW TUBERCLE BACILLI EXPELLED BY TUBERCULOUS COWS GET 
INTO MILK AND DAIRY PRODUCTS. 
It has been shown that seemingl}^ healthy, tuberculous cows expel 
tubercle bacilli directly with their milk and at one end of their bodies 
with saliva and particles of food and at the other end with feces. 
Consequently, we may justly conclude, if it can be shown that the 
material discharged by cattle per mouth and per rectum occurs fre- 
quently as a contaminating element in commercial milk, that the milk 
of tuberculous cows, and also of healthy cows that are stabled and 
milked together with tuberculous cows, will often be infected with 
tubercle bacilli. 
In one of the publications of the United States Public Health and 
Marine-Hospital Service the following statement is made about the 
milk of Washington, D. C., which is no worse than that of other cities: 
In addition to being warm, much of the milk is dirty. Fifty-one of 172 
samples examined showed no visible deposit in the original container after 
standing several hours. Fifteen of the samples contained a very small amount 
, of dirt, 98 contained a small amount of dirt, 8 contained much dirt, and 1 
j contained (mouse?) feces. 
The foreign matter (dirt) when examined under the microscope was found to 
i consist of fecal matter, hairs, epithelial and other cells, straw, bacteria, and all 
manner of extraneous substances that have no place in clean milk.® 
After several hours’ standing in the original containers, 121 of 172 
samples, or 70 per cent, of the kind of milk that reaches the consumer 
I showed a visible deposit of dirt, which was found on microscopic 
I examination to be made up in part of fecal matter, or that matter in 
which tuberculous cows most commonly expel tubercle bacilli. 
At the experiment station of the United States Bureau of Animal 
^1 Industry a large number of samples of milk, purchased from regular 
® Hygienic Laboratory Bulletin 35, p. 71. 
