J 94 BOARD OF AGRICULTURE. 



cells ; while the sugar of milk, also wanting in the blood, is 

 another result of this decomposition. According to them, 

 milk is formed by the transmutation of gland-cells; or, in 

 other words, the globules of milk were once cells or tissues 

 of the mammarj" glands, and not merely an exudation, or a 

 sort of straining of the blood through these glands. 



But other physiologists, whose opinion is entitled to equal 

 weight, maintain that the office of the milk-glands is cJiiefly 

 to separate the materials requisite for the formation of milk 

 from the blood, and to transform them into the constituents 

 which we find in milk, especially in milk-solids. They take 

 the ground that the caseine of milk is formed from the albu- 

 men of the blood through the agency of a peculiar ferment 

 which is found in the milk-glands ; and that the increase of 

 the caseine is always at the expense of the albumen of the 

 .blood. 



Without entering into this controversy, it is apparent, at 

 least, that the large amount of water in milk must depend 

 directly upon the blood itself, and upon the food which the 

 animal takes ; for we know perfectly well that very moist or 

 succulent food causes the milk to be. thin and watery as well 

 as abundant, showing that there must be a diffusion of water 

 directly from the blood. It is incredible that such great 

 quantities of water could be obtained from the decomposi- 

 tion of the gland-cells ; and, as water constitutes by far the 

 largest part of milk, it is practically correct to describe it as 

 a secretion from the blood, even if we admit that the milk- 

 solids have their origin in the decomposition of the mam- 

 mary glands. 



How, if the blood is poor, thin, and watery, if it is but 

 slightly charged with the fatty elements which have been 

 taken up in the food, the quality of the milk secreted from 

 this blood must of necessity be poor, because the quality or 

 richness of milk is supposed to depend on the amount or 

 proportion of fatty constituents, or what is more cominonly 

 known as cream and butter. And you will generally find 

 that the quality bears an intimate relation to the quantity 

 produced. 



The second step in the process of assimilation is, therefore, 

 the separation of a larger or smaller proportion of these fatty 

 elements in the blood, in the form of milk, the richness of 



