352 



MANUAL OF HISTOLOGY. 



of the skin, in the mamma during lactation, in the Meibomian and 

 ceruminous glands, as well as many of the sudoriferous organs. 



Thus we see the saccules of sebaceous glands (fig. 340, A) clothed on 

 their internal surface with cells (a), which 

 may be regarded as a modified prolonga- 

 tion of the Malpighian layer of the skin, 

 but which differ from the latter in being to 

 a certain extent rich in fatty granules (23, a). 

 By a further deposit of fat within the cell 

 the latter is increased in size (B, b-f), and 

 becomes detached from the membranapropria 

 (A, b), so that in the cavities of the organ 

 cells of 0-0377-0-0563 mm. are met with 

 elements in which the amount of fat is very 

 considerable. The latter presents itself 

 either in the form of innumerable granules 

 (B, b), or several globules of oil (c) enclosed 

 within the membrane of the cell, or, one 

 large drop communicates to the latter the 

 appearance of an ordinary fat cell (d). The 

 nuclei of these elements are gradually de- 

 stroyed, apparently, as also their envelopes, 

 at least frequently. Thus the secretion of 

 sebaceous glands contains, in the first place, 

 free fatty globules, and in the next place, 

 those cells loaded with oily matters just 

 described. 



A process precisely similar to this takes 

 place in the mamma of the nursing woman. 

 Here we see in the so-called colostrum (a 

 milk which is secreted during the later 

 period of pregnancy) round bodies of 

 0-0151-0-0563 mm. in diameter (fig. 341, 

 b), know as colostrum corpuscles, which are 

 simply aggregations of fatty particles of 

 varying size, held together by some agglutinating matter. At one time 

 they are seen to possess envelopes and nuclei, at another to be without 

 ^ n either. There can be no doubt that in these structures 



are presented to us the gland cells which have been 

 shed, and having undergone fatty degeneration, are 

 now in process of solution. 



Soon after delivery the milk contains innumerable 

 milk globules as they are called (a), that is, small 

 drops of oil enclosed in a delicate film of coagulated 

 casein. These bodies are of very different diameters, 

 measuring from 0'0029 to 0-0090 mm. In this case 

 the increased energy of secretion has led to rupture 

 of the gland cells while still within the organ. 

 In those situations where the gland cell possesses a finely granular 

 body consisting of albuminoid matters, we find it a matter of greater 

 difficulty to convince ourselves of the destruction of the former in the 

 formation of the secretion. "We usually meet, however, in the mucous 

 and peptic glands of the stomach with a certain number of liberated 



Fig. 340. Saccule of a sebaceous 

 gland, a, gland cells clothing the 

 walls ; 6, those which have heen cast 

 off, filled with oil globules, and occu- 

 pying the lumen of the sac; /?, the 

 cells under higher magnifying 

 power; a, smaller specimens belong- 

 ing to the parietal layer, and poor in 

 fat; b, larger, with abundance of the 

 latter; c, a cell in which several oil 

 globules have coalesced to form 

 larger drops ; and d, one with a 

 single fat globule ; e, /, cells whose 

 fat has partially escaped. 



k 



341. Form ele- 

 ments of human milk. 

 a, milk globules; 6, 

 colostrum corpuscles. 



