292 THE COMPLETE GRAZIER. BOOK ir. 



stalls to the tender soft herbage had something to do with the com- 

 plaint, caused a herd of milch cows to be fed with green food previous 

 to their going out on grass, commencing with small quantities of green 

 fodder, and gradually increasing this until it had wholly replaced the 

 other. The experiment extended over a fortnight, and at its close the 

 animals were put out to grass, but there were no complaints of lazy 

 milk. Hence, the abrupt change from dry to green fodder appears 

 sometimes to result in lazy milk, but why this should be so is not 

 known. Generally speaking, sudden and abrupt changes from one 

 kind of feeding to another should always be avoided, not on account 

 of the milk only, but for general considerations relating to health. 



It might be supposed that the more fat a food was found, on analysis 

 to contain, the richer would be the milk resulting from the consumption 

 of that food. But this is a generalisation not altogether warranted by 

 facts. Foster l significantly observes that the quantity of fat present in 

 milk is largely and directly increased by proteid (i.e., nitrogenous) food ; 

 but not increased, on the contrary, diminished, by fatty food. The 

 explanation of this is, that proteid food increases, and fatty food 

 diminishes, the metabolism of the body ; in other words, that it is the 

 nitrogenous constituents of the food-stuffs which excite the activity of 

 the living cells on whose protoplasm the maintenance of the functions 

 of the bod}' is dependent. A bitch fed on meat for a given period gave 

 off more fat in her milk than she could possibly have taken in her food, 

 and that too while she was gaining in weight, so that she could not 

 have supplied the mammary gland with fat at the expense of fat pre- 

 viously existing in her body ; she probably obtained it ultimately from 

 the proteids of her food. (It must be borne in mind that the proteids, 

 carbohydrates, and fats of animal food all contain carbon, hydrogen, and 

 oxygen, but that the proteids differ from the other two classes in also 

 containing nitrogen ; an animal could be kept alive on proteids alone, 

 but not on fats and carbohydrates either separately or together, a dog 

 fed exclusively on pure fat would die of starvation.) More than five- 

 and-twenty years ago, Lawes and Gilbert proved by direct analysis that 

 for every hundred parts of fat in the food of a fattening pig, four 

 hundred and seventy-two parts were stored up as fat during the fatten- 

 ing period, so that it is evident that fat is formed in the body out of 

 something which is not fat. And Liebig had previously proved that 

 the butter present in the milk of a cow was much greater than could be 

 accounted for by the scanty fat present in the grass or other fodder she 

 consumed. There is overwhelming proof that fat is formed anew in 

 the animal body, for two animals fed on the same food will each store 

 up the special kind of fat peculiar to itself. Moreover, dogs fed on 

 foods consisting largely of different fats will exhibit but little variation 

 in the composition of the fat they store up.' Subbotin found that a dog 

 fed after a preliminary starvation period, with one thousand grams of 

 spermaceti, of which he absorbed at least eight hundred grams, never- 

 theless yielded but the merest trace of spermaceti in the fat of his body. 



1 "Physiology." 



