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146 Report oF THE DrrEcTOR OF THE 
The Source of Fat in Milk. 
In the tenth annual report of this station we referred to the state- 
ment of Liebig that it was manifestly impossible that the scanty 
amount of fat in grass and fodder could account for the fat present 
in the milk of the cow, but as to, the statement it would be far ~ 
more readily accepted if the figures were given which prove it. 
It may be seriously questioned whether any cow fed entirely on 
grass or any other green fodder will for months continue to pro- 
duce more fat in her milk than careful analysis will show to be 
present in such grass or fodder. In the experiment recorded last 
year we found that the aggregate number of pounds of crude 
fat consumed by the animals under investigation was 4,587.9 and 
the aggregate amount of milk fat produced by them was 3,793.4 
pounds; or as 121 to 100. If we allow upon an average 17.4 per 
cent. of the crude fat as impurity, it would still leave fat enough 
in the food to account for all recovered in the milk. In the tenth 
report of this station there was given the averages of each animal 
for each month of lactation, and it was interesting to observe that 
during the earlier months the production of fat in milk was con- 
siderably in excess of even the crude fat of the food, but very soon 
the aniount of crude fat eaten and the amount produced became 
equal, and by a rather steady increase relatively the amount of 
crude fat consumed became at later months of lactation, largely in 
excess of the fat produced in the milk. Such a result appears to 
be in accord with common observation, since, as is well known, 
the cow and other animals, as the time of giving birth to their 
offspring approaches, often become dangerously laden with the 7 
accumulation of fat stored up in their bodies, and it is also a 
matter of common remark that soon after the period of lactation 
begins with the cow, this stored up fat, which seems to be a 
provision of nature to enable her to meet such emergency, dis- 
appears, only to reappear again when a like enereeney is to arise 
in the near future. . 
' During the past year these experiments have been continued 
and the previous results appear to be fully confirmed. 
The following table gives the results obtained from twenty ani- 
mals, in their first period of lactation. It will be seen that those’ 

