THE MAMMARY GLAND. 451 



Some liistologists, like Strieker, hold that oil-globules may be 

 expelled from the interior of fat-filled cells without disintegra- 

 tion of their protoplasmic bodies. It is an undoubtable fact 

 that colostrum corpuscles, when managed with proper precau- 

 tions, may be seen to yield droplets of fat under the micro- 

 scope, just as amoebae reject similar contained particles. Rau- 

 ber, however, maintains that these bodies represent leucocytes 

 in various stages of fatty metamorphosis, and he calls such 

 corpuscles, when found in the gland vesicles, galactoblasts. 



In the gland of Harder, one of the writers has found the 

 spacious gland vesicles lined with very large epithelia ; and 

 these cells were in many animals entirely fat-filled. They se- 

 creted a greasy substance not unlike thick milk. Yet destruc- 

 tion of the cell-body did not occur, at least evidences of such 

 a process could not be obtained. Partsch has therefore antici- 

 pated the authors in their conclusion that the secretion of milk 

 is accomplished in much the same way in which the creamy pro- 

 ducts of the Harderian gland are formed, i.e., without total 

 destruction of epithelial cells. According to our view, then, 

 and it nearly coincides with the opinion of Strieker, Winkler, 

 and especially Partsch, the cells containing the fat-globules 

 may, indeed, burst and discharge their contents, but the nu- 

 cleus and sufficient protoplasm are retained to enable the epi- 

 thelium to recuperate, and in the course of time again and 

 again discharge its contents. Along with this mode of milk 

 secretion, a second process occurs. This consists of the gradual 

 extrusion of oil-droplets, the cell body remaining entirely in- 

 tact, since the mere vital contractions of the protoplasm suf- 

 fice to drive out one milk-globule after another. 



When the activity of the gland is suddenly heightened in 

 the period immediately before childbirth, some few epithelial 

 cells are desquamated. These, appearing in the milk of most 

 women, are identical with the bodies known and described as 

 colostrum corpuscles. 



Of other anatomical constituents of normal milk, we only 

 find the milk- or oil-globules. They are suspended in the fluid 

 emulsion which milk truly represents, in countless numbers. 

 They vary in size from 0.002 to 0.009 mm. A very delicate 

 fringe of protoplasm adheres to their periphery, and it is for 

 this reason that they may appear to become stained when sub- 

 mitted to the action of proper dyes. 



