COLOSTRUM. 103 



the first few days after delivery, is called colostrum. It is 

 yellowish, semiopaque, of a distinctly alkaline reaction, and 

 somewhat mucilaginous in its consistence. Its specific gravi- 

 ty is considerably above that of the ordinary milk, being from 

 1040 to 1060. As lactation progresses, the character of the 

 secretion rapidly changes, until it becomes loaded with true 

 milk-globules and assumes the characters of ordinary milk. 



The opacity of the colostrum is due to the presence 'of a 

 number of different corpuscular elements. Milk-globules, very 

 variable in size and number, are to be found in the secretion 

 from the first. These, however, do not exist in sufficient 

 quantity to render the fluid very opaque, and they are 

 frequently aggregated in rounded and irregular masses, 

 held together, apparently, by some glutinous matter. Pecu- 

 liar corpuscles, first accurately described by Donne, un- 

 der the name of " granular bodies," and supposed to be 

 characteristic of the colostrum, always exist in this fluid. 1 

 These are now known as colostrum-corpuscles. They are 

 spherical, varying in size from 2 ^ Qd to -g-^j- of an inch, are 

 sometimes pale, but more frequently quite granular, and 

 contain very often a large number of fatty particles. They 

 behave in all respects like leucocytes, and are described by 

 Eobin as a variety of these bodies. 3 Many of them are pre- 

 cisely like the leucocytes found in the blood, lymph, or pus. 

 Their appearance was very well described by Donne, who 

 supposed that they were mucus-corpuscles. 3 We now know, 

 however, that the so-called mucus-corpuscle does not differ 

 from the pus-corpuscle or the white corpuscle of the blood ; 

 and leucocytes generally, when confined in liquids that are 

 not subject to movements, are apt to undergo enlargement, 

 to become fatty, and, in short, present all the different ap- 

 pearances observed in the colostrum-corpuscles. In addition 



1 DONNE, Cours de microscopic, Paris, 1844, p. 400. 



2 ROBIN, Sur quelques points de ranatomie et de la physiologic deft leucocytes. 

 Journal de la physiologic, Paris, 1859, tome ii., p. 56. 



8 DONNE, loc. dt. 



