440 THE GLANDULAR O&GANS. 



Ferments. At least three ferments seem to occur in cows' milk, 

 viz., a milk-trypsin, a milk-katalase, and a milk-peroxydase. In 

 addition Babcock and Russell have described a galaktase. In 

 human milk there is a diastase (absent in cows' milk), very little 

 if any peroxydase, but more katalase than in cows' milk ; and in 

 addition a proteolytic ferment. Possibly still other ferments are 

 present. 



Colostrum. 



The term colostrum is applied to the secretion of the mammary 

 glands which is furnished by the female animal during the first 

 days of lactation, and which may also be expressed from the glands 

 during a variable period preceding parturition. 



On microscopical examination such fluid is seen to contain innum- 

 erable fat-globules, and in addition a variable number of granular 

 cells, which are capable of manifesting amreboid movements. These 

 are termed colostrum-corpuscles, and are commonly regarded as 

 leucocytes. This, however, is doubtful. According to Woodward, 

 they have a small irregular, but much degenerated nucleus. Of the 

 granules, a few are stained by osmic acid, while none of them takes 

 up either acid, neutral, or basic dyes. In their reactions they show 

 the characteristics of proteid material. 



The secretion is a thick yellowish fluid, of an alkaline and some- 

 times acid reaction, and a specific gravity that is much higher than 

 that of true milk. In the cow this varies between 1.046 and 

 1.080, and in the human female between 1.040 and 1.060. This is 

 principally owing to the presence of large amounts of lactalbumin 

 and lactoglobulin. As a consequence, the colostrum coagulates 

 on boiling, while true milk, as we have seen, is then covered merely 

 by a skin, which is composed of casein and calcium phosphates. The 

 total quantity of the coagulable albumins may reach 15 per cent., 

 while in milk about 0.5 per cent, is the rule. 



The amount of casein and of mineral salts in colostrum is also 

 somewhat greater than in milk, and it is further stated that more 

 lecithin and cholesterin is present. The quantity of fat is practi- 

 cally the same, while that of lactose is somewhat smaller. As a 

 result of the increase in the amount of albumins and of mineral salts, 

 the total solids are also proportionately increased, and may amount 

 to 25.3 per cent, in cows' colostrum, as compared with 12.8 per cent, 

 in the case of the milk. 



The quantitative composition of the colostrum after parturition is 

 rapidly altered, so that after a few days already the normal compo- 

 sition of true milk is approached. This is well shown in the follow- 

 ing table, which is taken from Gautier. The results have reference 

 to the human being and the cow, and are expressed in percentages : 



