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During the last few years a considerable change has 

 occurred in the feeding of cows by the introduction of Indian 

 cotton cake. The Indian cotton seed from which the cake 

 is prepared, is often kept in store under damp conditions, and 

 the seed is apt to become mouldy or discoloured, to prevent 

 which boric acid is used as a preservative. Whilst some 

 samples of Indian cotton cake are free from boric acid, others 

 contain nearly 1 per cent. ; and whilst some dairy farmers 

 do not use Indian cotton cake at all, others have used as 

 much as 12 Ib. a day to each cow 1 .. Under such circum- 

 stances it has become necessary to carry out experiments to 

 determine whether under these new conditions cows' milk 

 may or may not contain boric acid. The subject is the more 

 important because a farmer selling milk containing boric acid 

 is liable to prosecution for adulteration. 



EXPERIMENT M. 



Two cows were fed on 5 Ib. maize meal and 3 Ib. decorti- 

 cated cotton cake, with sufficient straw chaff and hay through- 

 out the experiment, whilst two other cows were fed the same 

 in all respects except that they received a small quantity 

 of "boric meal" made from 19 parts of maize meal and 1 

 part of boric acid, instead of an equal amount of pure maize 

 meal. The boric meal used contained 5 per cent, of boric 

 acid, of which from J Ib. to 1 Ib. was fed. All the other 

 foods used were tested for boric acid and found to be free from 

 that impurity. 



It is interesting to note that boric acid appeared in the 

 milk as soon as the cows received a ration containing any 

 boric acid, although there is a slight "lag" in the amounts, 

 since the cows did not reach the maximum amount of boric 

 acid in the milk till three days after receiving the maximum 

 amount of boric acid in the food. The amount of boric acid 

 returned is very small, being only one fiftieth part of the 

 amount fed, yet this small amount would be sufficient to 

 render the milk seller liable to prosecution under the Food 



