420 MAl^TJAL OF CATTLE-FEEDlJSra. 



able, in investigations on milk production, to introduce at 

 the end of each series of experiments a period in wliidi 

 the fodder is the same as in the first period, in order to be 

 able to take account of the extent of this diminution. 



The Supply of Protein.— The formation of milk con- 

 sists essentially in a rapid growth of new cells in the milk- 

 glands. These cells consist largely of protein, and we 

 should therefore expect their formation to be more or less 

 dependent on the supply of protein in the food. More- 

 over, not only the protein of the milk, but also its fat, and 

 perhaps part of its sugar, appear to be formed from albu- 

 minoids, and thus a further necessity for an abundant snp^ 

 ply of these substances arises. 



In fact, all experiments agree in showing that the great- 

 est yield of milk is obtained with a fodder rich in protein. 

 The size and quality of the milk-gland, it is true, deter- 

 mine the maximum amount of milk that can be formed, 

 but this maximum can be reached only by means of a lib- 

 eral supply of protein. 



Another effect of protein, which shows itself in all ex- 

 periments, is to augment the percentage of sohd matter in 

 the milk — L ^., to make it less watery. Since, now, the 

 amount of real production which takes place, as well as 

 the true value of the milk, is measured by the amount of 

 solid matter in the latter, it is evident that w^e nnist reduce 

 the quantities of milk produced in any experiment to a 

 uniform w^ater-content before we can properly compare 

 them. The basis usually adopted is ^S per Qmi. .-.w^ater 

 and 12 per cent, solid matter, and from the actual quantity 

 of milk produced is calculated the quantity which would 

 have been produced had the amount of solid matter 

 present been contained in milk having 88 per cent of 

 water. 



