160 ORGANISED FLUIDS. 



globules, and all of them are flat and semi-fluid. (See Plate 



xv. jig. a.) 



The several facts now adduced, while they prove that the 

 milk globule is not organised in accordance with the inter- 

 pretation of the word organisation usually gi\ 7 en, yet seem 

 sufficient to establish the f%ct that it is composed of two 

 distinct organic products, the one internal and fatty, and the 

 other external and possessed of properties distinct from fat. 



This explanation of the constitution of the milk globule 

 serves to explain also satisfactorily the facts above alluded to, 

 viz. the non-action of boiling water, alcohol, and alkalies, all 

 of which affect more or less fat, as also the slower operation 

 of the ether : it also shows why boiling alcohol should imme- 

 diately dissolve the milk globules, to which a little acetic 

 acid had been previously added, this latter re-agent first re- 

 moving their outer coating, which is insoluble in alcohol. 



Between the globules of the previously described fluids, 

 those of the lymph and chyle, of the blood, mucus and 

 pus, and the globules of milk, no structural or functional 

 relation whatever exists, the former being complex and 

 definite organisations or cells, and the latter constituted of 

 two distinct substances indeed, yet want entirely the attri- 

 butes of cells, being destitute of nucleus and cell wall. 



It is of the globules just described that the cream is con- 

 stituted, their accumulation on the surface of the milk being 

 due to their lighter specific gravity ; it is also by their incor- 

 poration with each other, and which is effected by the opera- 

 tion of churning, that butter is formed. 



COLOSTRUM. 



The milk which is secreted the first few days after childbirth 

 has been denominated colostrum : it differs very considerably 

 from ordinary milk, being of a yellow colour, of a viscous 

 consistence, and containing a very large proportion of milk 

 globules, which give rise to the formation upon it of a thick 

 layer of cream ; when treated with ammonia it becomes glairy 

 and tenacious. 



