COLOSTRUM. 161 



are strange. Thus Dyer has recorded an analysis of milk obtained 

 from a cow at an agricultural show which contained 1'85 per cent. 

 of fat ; the next day the milk was normal, containing 3'64 per 

 cent, of fat. Many, if not all, of the very low fats recorded in 

 Table XXIV. on p. 156 are due to this cause. 



Colostrum. — The name " colostrum " is applied to the secretion 

 of the udder before (and immediately after) parturition. Las- 

 saigne pointed out that an albuminous liquid commenced to form 

 sometimes two months before parturition. This secretion, accord- 

 ing to Houdet, often appears under two forms — a brownish, 

 viscous, honey-like product, and a lemon-yellow, non-viscous 

 liquid ; the two often co-exist in the same animal, the earlier 

 milkings furnishing the first, and the later the second. 



The viscous secretion is curdled by heat, and precipitated by 

 acetic acid, mercuiic chloride, and alcohol, but not curdled by 

 rennet. The analysis is 



Pli ci-nt. 



Water 63-14 



Soluble protein 2274 



Ck)Uoidal „ 1412 



Ash, ........ trace 



The non-viscous secretion contained more water and less 

 soluble protein than the viscous secretion, and gave a barely 

 appreciable precipitate with mercuric chloride and alcohol, but 

 was coagulated by heat and acetic acid and unaffected by rennet. 



One hundred cubic centimetres contained 



Fat, . 



Sugar, 



Soluble proteins, 



Colloidal „ 



Calcium phosphate, 



Other salts, 



015 gramme. 



0-80 



1-38 



4-39 



0-11 



0-38 



Total solids, . . 7-21 



The composition of the fluid secretion approaches more nearly 

 to that of milk. 



Four or five days before parturition the secretions are replaced 

 by colostrum proper. 



True colostrum is an opaque yellow liquid of pungent taste : 

 sometimes blood is present, which shows its presence by a reddish 

 colour. 



It is curdled by heat, acetic acid, mercuric chloride, and rennet 

 (though the action of this is not so rapid as with milk). It has 

 a slimv, viscous appearance, and, if left to stand, has a tendency 

 til separate into two layers. 



The proteins probably consist of casein, albumin, nuclein, and 



