200 THE 



tilling the vesicles ; thus the entire gland becomes en- 

 larged in size (figure 23, h) and firm to the touch, and 

 as parturition approaches this increased size and firmness 

 are intensified, until delivery takes place, when the vesi- 

 cles break down, the albuminous serum with the fat 

 globules escape, gather into tlie lactiferous tubes, and 

 collect in the sinuses or reservoirs. This process goes on 

 more or less actively in proportion to the natural ability 

 and the liberal nutrition of the cow to supply the mate- 

 rials for the enormous loss of tissue. 



Milk is easily analyzed and its constituents separated, 

 and every dairyman should be able to perform this oper- 

 ation for himself. The separation of the fat is the mat- 

 ter of greatest moment, although it is quite as ofteii 

 desirable to know" the quantity of caseine contained in it. 

 It is necessary to procure a pair of delicate scales with 

 weights and measures of the metric or decimal system, 

 grams for weighing, and a one hundred centimeter rule 

 for measuring. One hundred cubic centimeters of the 

 milk at sixty degrees of temperature are measured and 

 weighed, and the weights noted ; this milk is set apart 

 for the cream. Five centimeters are then weighed, evap- 

 orated to dryness, and w^eighed again ; the difference is 

 the water and the weight the total solids. The fat is then 

 dissolved out by benzine and the loss after the benzine 

 has been wholly evaporated is the quantity of fats. There 

 are then left the caseine, sugar and salts. The residue 

 left by the benzine is weighed and is then burned com- 

 pletely. The last result, the ash, is then weighed. The 

 caseine and sugar are then to be determined. Twenty- 

 five centimeters of the skimmed milk are curdled by the 

 addition of acetic acid, and the curd separated, dried and 

 weighed. The whey may be then evaporated, washed 

 in benzine, and then weighed and burned ; the loss is the 

 sugar. In this way every constituent may be easily calcu- 

 lated. But the character of milk is as yet far from having 



