Effect of Oil-Cake on Butter. 



207 



and the cows turned out to grass. On the 26th May, and 

 about every alternate day till the 17th of June, samples were 

 taken from the first set of cows (Nos. i to 4), and the results 

 of their examination showed that the cottonseed oil reactions 

 persisted in a distinct form for about three days, and were 

 distinguishable in the butter from three out of the four cows 

 on the fifth day. At the end of a week it had disappeared 

 from all. 



In a number of samples the reactions given by the tests for 

 cottonseed oil were carefully compared with those given by 

 similar butterfats to which i, 2, and 5 per cent, of four repre 

 sentative samples of commercial cottonseed oils had been 

 added. From a comparison of the results of the tests, it was 

 apparent that the strongest reactions from the samples from 

 the cows fed on cottonseed cake did not much exceed that 

 given by i per cent, of cottonseed oil added to butter, and the 

 great majority of the samples gave reactions indicating less 

 than I per cent. — reactions which would, indeed, be almost 

 obscured in butter prepared and coloured in the ordinary 

 manner. 



On several occasions the Principal of the College prepared 

 butter in the ordinary way from the mixed milks of the cows 

 in the respective sets. The results of the examination of 

 samples of these butters were similar to those from the 

 individual cows, the intensity of the cottonseed oil reaction 

 being midway between the weakest and strongest cows in 

 the set. These butters were, however, uncoloured, and the 

 reactions were consequently not obscured. 



The general conclusions to be drawn from these experi- 

 ments may be summed up as follows : — 



1. Cows fed on cottonseed oilcake produce milk, the butter- 

 fat of which gives cottonseed oil reactions. 



2. The reactions appear when the cows receive only a 

 small quantity of cake. They increase somewhat with 

 continuous feeding, but apparently cannot be carried beyond 

 a certain point even when the amount of cake is increased to 

 the full limit which the cows under ordinary circumstances 

 care to eat. 



3. The reacting substance passes into the milk within less 



