383 
ent animals, but practically constant for the normal milk of any 
particular animal species. He gives the following values for the 
index of oxidation of the milk of the following animals : 
Ass 55-58 
Woman 53-60 
Cow 50-52 
Goat 44-i6 
Sheep 43^8 
He also finds that the value of the index of oxidation of cow’s 
milk diminishes with the amount of water added, and also with 
skimming. Thus the index of oxidation of cow’s milk containing 50 
per cent of water was found to be 25, and that of skimmed milk 40 
1 to 42. 
According to Atkins (4) , determinations of the freezing point and 
* of the specific gravity of milk are sufficient to show whether water 
has been added or fat removed. 
' The addition of water to milk is not only a fraudulent practice 
and one which as such should be condemned, but it may frequently 
be a serious menace to the public health. Atlee (5) has pointed out 
that impure water is one of the most frequent sources of milk pollu- 
tion. This pollution may occur either through the use of impure 
water for purposes of adulteration or as the result of washing the 
milk containers and utensils in polluted water. As is well known, 
milk is one of the best possible culture media for the growth of micro- 
organisms, especially for many of the pathogenic bacteria. It is 
conceivable, therefore, indeed it is a well-known fact, that the intro- 
duction of a fcAv pathogenic organisms into milk through the addi- 
tion of impure water will under certain conditions give rise to a 
fluid containing countless numbers of such organisms. In this way 
the adulteration of milk with water may give rise to a widespread 
dissemination of various infections, especially typhoid fever, diph- 
theria, scarlet fever, etc. Aside therefore from the fraudulent aspect 
;of the practice, the adulteration of milk with water, from any and 
.every source, as frequently happens, becomes a matter of serious con- 
Icern, and of all fraudulent and uncleanly practices resorted to in the 
handling and sale of milk this and the uncleanly methods of handling 
milk are the two which should be most vigorously combated and 
condemned. 
Thickening agents . — As indicated above, the adulteration of milk 
through the use of thickening agents, such as chalk, calves’ brains, 
Iglycerin, etc., has largely passed out of vogue. Indeed it is doubtful 
^whether any of these substances were ever used to any considerable 
extent, despite traditions to the contrary. According to Van Slyke 
(6) gelatin and sucrate of lime are used to some extent to give a 
greater consistency to cream. In this connection Babcock and 
[ Russell have recommended the use of sucrate .of lime for restoring 
The consistency of pasteurized cream. (See Leach (1), p. 15G.) 
