i2) SOUTHERN CALIBNORNIA ACADEMY OF SCGIENGES 
Much of the milk delivered to the city through the depots 
is pasteurized, that is, exposed to a temperature between 65 
and 70 C., by which a great number of bacteria are destroyed. 
Milk brought in by dairymen showing 16,000,000 bacteria to 
le. ¢. after pasteurization shows a count of 100,000 per cu. em. 
While pasteurization might partially settle the question of 
clean milk it would put the small dairymen out of business and 
restrictions about cleanliness would be in a great measure 
removed. Lactic acid and other bacteria are destroyed which 
are necessary for the flavor in butter and cheese. During the 
past year the bacterial count at the dairies has conformed to 
the standard of 500,000 colonies per cu. em., most of the best 
dairies showing from 50,000 to 300,000. The particular dis- 
advantages for clean milk in Southern California are the dust, 
the warm days and transportation from the dairy to the con- 
sumer. Dairies on the electric lines have a decided advantage 
over thost whose milk is brought to the city in wagons. The 
average number of bacteria in milk delivered to the consumer 
in Los Angeles is between 1,000,000 and 3,000,000 to one «. e. 
While this may seem an enormous number of germs (48,000,000 
In an ordinary glass of milk) very few of this number are 
pathogenic. A comparative study of the bacteriological stand- 
ards of other cities is of interest: 
Munich, 200,000 to 6,000,000. 
Wurzbure, 222,000 to 23,000,000. 
Boston, 30,000 to 4,220,000. 
Middletown, Conn., 11,000 to 85,500,000. 
Sewage, 100,000 to 4,000,000. 
The different species of bacteria found in milk are about 200, 
Many of these are necesary for the production of flavors in 
butter, cheese and in the milk itself. Among the more import- 
ant contagious diseases probably transmitted by milk, are 
tuberculosis, diphtheria and typhoid fever. 
The most important work along dairy lines of the Los Ange- 
les Health Department for the year is the appointment of a 
veterinarian, Dr. L. W. Young, whose three months of work 
have been productive of great good. Many diseased animals 
have been removed frof dairy herds, suffering principally from 
tuberculosis and actinomyeosis, and after all our main hope 
for the future must be in removing of diseased animals from 
dairy herds. 
