BY H. S. HALCRO WAItDLAW. 



855 



12. The calculated mean values are, therefore, not so strictly 

 comparable as if the numbers of the cows of each strain were 

 approximately equal. 



Table vii. 



The values given in this Table show that the greatest range of 

 variation occurs in the mean percentage of fat, which is greatest 

 in the case of Crossbred cows(5"5%), and least in the case of 

 Shorthorn strains (4"8%). The mean yield of milk, on the other 

 hand, is greatest in the case of the Jersey strain (4-3 kg.), and least 

 in the case of the Crossbred (3*4 kg.). The mean total weight of 

 fat obtained at a milking is greatest in the case of the Jersey 

 strain (21 3 gm.), and least in the case of the Shorthorn (I79gm.). 

 The mean percentage of lactose is highest in the Jersey strain 

 (5*05%), and lowest in the Crossbred and Ayrshire(4-85%). The 

 mean percentage of ash is greatest in the Crossbred cows(0"72%), 

 and least in the case of the Ayrshire strains (0"66%). The mean 

 percentage of protein and extractives is greatest in the milk of 

 cows of Ayrshire strain (3"1%), and least in that of cows of 

 Crossbred and Ayrshire strains (3-0%). Its range of variation 

 is small. 



