COLOSTRUM- AND MILK-CORPUSCLES. 377 



trum and sebaceous matter differs in this respect only, 

 that the fat-granules remain smaller in the former case, 

 and that whilst large drops very soon show themselves 

 in sebaceous matter, in colostrum the last cells which 

 are observed, usually contain only minute fat-granules, 

 very densely aggregated, whereby the whole cell ac- 

 quires a somewhat brownish appearance, although the 

 fat has no actual colour. This is the granular corpuscle 

 (corps granuleux) of Donne". 



Foi the discovery of this gradual transformation of 

 cellular bodies into fat-granule masses we are indebted 

 to Reinhardt. Still he shrank from extending this 

 important discovery of the formation of colostrum to 

 the history of milk in general, for the reason, that, 

 during the later periods of lactation properly so-called, 

 granulated bodies are no longer met with. It is, how- 

 ever, unquestionable, that between the earlier formation 

 of colostrum-corpuscles and the later one of milk, there 

 is no other difference than this, that in the formation of 

 colostrum the process goes on more slowly, and that the 

 cells maintain their cohesion longer, whilst in the secre- 

 tion of milk the process is acute and the cells more 

 speedily perish. Perfectly developed colostrum con- 

 tains an extremely large number of granulated cor- 

 puscles, milk nothing more than a number of compara- 

 tively large and small drops of fat, mixed up together, 

 the so-called milk- corpuscles (Fig. 112, B), which are 

 nothing more than drops of fat, and like the majority of 

 the drops of fat that occur in the animal body are sur- 

 rounded by a delicate, albuminous membrane, called by 

 Ascherson the haptogenic* membrane (haptogenmem- 

 bran). But the individual drops (milk-corpuscles) cor- 

 respond to the drops which we find in the secretion of 



* 1. ., produced by contact. TRANSL. 



