288 Dr. Lyon Playfair on the Milk of the Cow, 



Contained only 0-486 lb. of fat, so that 0*485 lb. of buttef 

 nmst have been produced from other sources. 



2. The food received by the cow on the 3rd day consisted 

 of 28 lbs. of hay, 2^ lbs. of oatmeal, and 8 lbs. of bean-flour. 



28 lbs. of hay contain . . . 0-436 lb. of fat. 

 2\ lbs. of oatmeal contain . - 050 lb. of fat. 

 8 lbs. of beans contain . . 0*056 lb. of fat. 



In the food . . . . 0*542 lb. of fat. 



The milk of the evening amounted to 10*34 lbs., and con- 

 tained 0*4 lb. of butter; that of the morning to 11*61 lbs., and 

 contained 0*5 lb. of butter. The butter in the milk amounted, 

 therefore, to 0*9 lb., of which only 0*542 lb. could possibly 

 have been furnished by the food, assuming that the fat in the 

 food could be converted into butter. 



3. The cow received on the 4th day 14 lbs. of hay, 8 lbs. 

 of beans, and 24 lbs. of potatoes. 



14 lbs. of hay contain . . '. 0*218 lb. of fat. 



8 lbs. of beans contain . . 0*056 lb. of fat. 



24 lbs. of potatoes contain . 0*072 lb. of fat. 



0*346 

 The evening's milk amounted to 12*9 lbs., and contained 

 0*86 lb. of butter; that of the morning to 10*32 lbs., and con- 

 tained 0*50 lb. The cow, therefore, furnished during the 

 day 1*36 lb. of butter. The fat in the food amounted only 

 to 0*346 lb., and therefore 1*064 lb. must have been received 

 from other sources. 



4. On the 5th day the cow received 14 lbs. of hay and 

 30 lbs. of potatoes. 



14 lbs. of hay contain . . . 0*218 lb. of fat. 

 30 lbs. of potatoes contain . 0*090 lb. of fat. 



0*308 



The milk of the evening amounted to 13*18 lbs., and con- 

 tained 0*606 lb. of butter; that of the morning to 12*20 lbs., 

 containing 0*597 lb. of butter. The cow, therefore, furnished 

 1*203 lb. of butter. The fat in the food amounted only to 

 0*308 lb. Hence 0*895 lb. of butter must have been pro- 

 duced from other sources. 



From these calculations it must be obvious, that the butter 

 in the milk could not have arisen solely from the fat contained 

 in the food. Hence it must have been produced by a separation 

 of oxygen from the elements of the unazotised ingredients of 

 the food of the animal, in the manner pointed out by Liebig. 



We remark striking variations in the quantity of butter in 

 the preceding analysis, and a similar result occurred in the 



