MILCH-KINE. 451 



The small quantity of butter here induced me to repeat the analy- 

 sis, but the result came out very nearly the same, the quantity being 

 still but 2.35 per 100. 



4th EXPERIMENT. 



204 DAYS AFTER THE CALVING. 

 Green fodder : same quantity as before. 

 Milk per day 13.7 pints, composed of : 

 Caseum 8.7 ^ 



lugr„fm,,i-.-.;::;:;:::::;:;::ll[s«ua»«-6 



Ash of caseum 0.2 ; 



Water 87.4 



100.0 



It would therefore appear that fresh-cut clover has no such virtue 

 as that of increasing the quantity of milk given by cows. Under 

 the winter fare, in fact, the milk produced in the course of the 

 twenty-four hours amounted to 16.7 pints ; under green clover it 

 was but 14.9 pints. It would be a great mistake, however, as I 

 conceive, to ascribe the diminution here to the use of the green 

 forage ; it is due, I apprehend, exclusively to the greater length of 

 time that has elapsed since the period of calving. 



The chemical composition of the milk varied little, as I have 

 already incidentally remarked, in the course of these experiments. 

 The differences in respect of the caseum, by which let me say I 

 understand the whole of the azotized constituents, the whole flesh 

 of the milk, rarely exceed one hundredth part. The proportion of 

 the fatty element varies suddenly, and, as it seems, independently 

 of the various circumstances in which the cows are placed. 



The general inference from these experiments, then, is that the 

 nature of the food does not exert any marked influence on the quan- 

 tity and chemical constitution of the milk (I do not now speak of 

 the quality of the fluid) if the cows but receive the proper nutritive 

 equivalents of the several sorts of provender. It is of great impor- 

 tance to insist on this point ; for it is quite certain, that if the 

 weight of the several rations be not calculated according to that of 

 the equivalents, variations in the secretion of milk would be forth- 

 with conspicuous ; but then these variations would have the increase 

 or diminution of the provender allowed as their cause. 



When cows are kept through the winter upon straw alone, they 

 cease to give milk ; but on the return of green forage, in the spring, 

 the secretion is restored. The re-appearance of the milk in this 

 case, however, is not connected with the coming in of the fresh 

 provender, but with the return of plenty ; the animals are not only 

 fed, from having been starved, but they are more than fed ; they 

 have something to spare, which their economy turns partly into milk. 



In well-managed establishments, where a good system of hus- 

 bandry secures an abundant supply of good nutritive provender to 

 the cattle during winter, the produce of the dairy during this season 

 differs much less from that of the summer than is generally supposed. 

 I am besides persuaded that we estimate the nutritive powers of 



