TYPHOID FEVEE IN DISTKICT OF COLUMBIA. 
71 
to the sanitary code of New York and would have been excluded 
from sale according to the health regulations of the city of Boston 
on account of the temperature alone. 
DIRTY MILK. 
In addition to being old and warm, much of the milk sold in Wash- 
ington is dirty. Fifty-one of the 172 samples examined showed no 
visible deposit in the original container after several hours’ standing. 
Fifteen of the samples contained a very small amount of dirt, 98 
contained a small amount of dirt, 8 contained much dirt, and 1 con- 
tained (mouse ?) feces. 
This foreign matter (dirt) when examined under the microscope 
was found to consist of fecal matter, hair, epithelial and other cells, 
straw, bacteria, and all manner of extraneous substances that have 
no place in clean milk. 
We made no quantitative w^eighings of the amount of dirt found 
in our samples, but only took note of the foreign matter visible to 
the naked eye, which settled down after a few hours’ standing. Any 
housewife may satisfy herself of the presence or absence of foreign 
matter by this simple test. Good, clean milk should show no such 
deposit. 
Comment upon this part of our work seems unnecessary. It is 
true that hair, cow excrement, and other substances found in the 
milk do not of themselves breed disease, and may not be so dangerous 
as the invisible pathogenic germs; but the one is as undesirable as 
the other is dangerous. The fact that such extraneous substances 
gain entrance to the milk in such large quantities is a sad commentary 
upon the cleanliness used in milking and the after care of the milk, 
and is an index of how readily the more insidious and less evident 
infections of Gq)hoid fever, diphtheria, scarlet fever, etc., may like- 
wise contaminate the milk. 
THE NUMBER OF BACTERIA IN MILK. 
The samples of milk were brought to the laboratory on ice, and as 
soon as received were plated upon agar-agar in Petri dishes in the 
usual way. Thb plates were incubated at 37° C.^ and the number of 
colonies which developed were counted by Mt. William Lindgren 
after twenty-four hours, sometimes at the end of forty-eight hours, 
in order to obtain a maximum growth. 
The number of bacteria in a cubic centimeter of milk is no index of 
its contamination with typhoid; it is only an indication of the age, 
temperature, and cleanliness of the milk. 
A study of the table shows that only 29 of the 172 samples examined 
contained less than 500,000 bacteria per cubic centimeter. The great 
