INFLUENCE OF THE PLANE OF NUTRITION UPON MILK 67 
gaira-Luto as modified by Rosenthal and Trowbridge.’ Table 
V gives the results. 
TABLE’ V 
INFLUENCE OF UNDERFEEDING ON PERCENTAGE OF FAT IN BLOOD AND 
PERCENTAGE OF FAL IN MILK 
Daily *Pat Fat in Blood 
Date Lactation milk in 
yield milk Test 1 Test 2. | Average 
Days Pounds | Per cent | Per cent | Per cent | Per cent 
Cow 407 
1914 
Dee. 24 SSI thaaiecche tate wae hee etiaats 0.484 0.396 0.440 
1915 
Jan. 5 3 46.1 6.80 2318 328 323 
Jan. 6. 4 33.7 4.80 2S «B15 298 
Feb. 16. 45 49.5 3.65 2323 2824 324 
| 
Cow 305 ; 
1915 | 
Feb. ee ee ee eee 257 Lost 257 
Feb. 2 24.3 6.46 241 223 232 
Feb. 3 27.0 6.68 237 e021, 229 
Feb. 4 29.8 6.10 +210 Lost 210 
Feb. 11 33.1 6.10 +233 Lost 233 
Mar. 20 38.0 5200. Psnctcsh accliietece tens leone ees ¢ 
* The average of Cow 407 for the year was 3.36 and of Cow 305, 4.08 per cent. 
The negative results obtained on the blood fat seem to in- 
dicate that in the case of the cow, starvation does not result 
as is the case with small animals in an increase in the fat in 
the blood. It would seem therefore that the increase in the 
fat in the milk could hardly be looked upon as the result of 
a direct transfer from the body. 
It is believed the explanation may be sought along other 
lines and the following is suggested. When the body is forced 
to draw on its reserves for needed energy, the fat is liberated 
by an increased lipase activity. The hormone or chemical 
messenger that stimulates this lipase activity must be carried 
by the blood, and it is reasonable to believe that it will affect 
the lipase activity in all parts of the body through which 
7H. Rosenthal and P. F. Trowbridge, The Estimation of Fat in Blood 
in J. Biol. Chem., 20, pp. 711-717, 1915. 
