DEVELOPMENT OF CITY MILK SUPPLY PROBLEMS 37 
carbon and passing it through a 100-mesh to the inch sieve. 
The desired amount of this carbon is then weighed in a ground 
glass slide and transferred to a small beaker containing 50 
ce. ¢c. of milk. After stirring until uniformly distributed, the 
contents of the beaker, while rotating, are poured quickly into 
the sediment tester. The carbon is deposited upon the cotton 
disk in the tester and this disk may be used as a standard 
for comparison with disks resulting from the testing of milk 
samples.”4 
Standards prepared in this way are quite uniform and in 
the lower dilutions clearly show differences of 0.25 milligram. 
A series of these standards may be conveniently mounted on 
a card and protected from dirt by a strip of glass or celluloid. 
With such a series of standards at hand, the making of a sedi- 
ment test from a sample of milk and the estimation of the 
amount of dirt present by comparison with these standards 
occupies but two or three minutes. 
Tur PRoBLEM or KEEPING QUALITY 
The first article prepared by Dr. Russell for his first annual 
report was entitled The Source of Bacterial Infection and the 
Relation of the Same to the Keeping Qualities of Milk.> At 
that time the idea was almost universal that the overshadow- 
ing importance of bacteria in milk lay in their relation to 
the health of the consumer. A portion of this fear of germ 
life arose from the feeling that since certain germs cause 
definite diseases, all germs must be dangerous. The faulty 
logic in this reasoning is too evident to need discussion. The 
nightshade is truly a poisonous plant while its near relative, 
the potato, is one of our most important sources of food. 
The fact that the death rate of babies is highest during the 
hot months when the germ content of the milk supply is also 
highest early led to the belief that the high germ content 
* The details of the preparation of these standards were worked out by 
James D. Brew under the general direction of the author. 
2H. L. Russell, The Source of Bacterial Infection and the Relation of 
the Same to the Keeping Qualities of Milk in Annual Report, Wis. Agr. 
Exp. Sta., 11 (1894), pp. 150-165, 1895. 
