REGRESSIVE METAMORPHOSIS OF MAMMARY GLAND. 285 



of S. Strieker,* who is of opinion that the detached colostrum 

 cells swimming in fresh milk excrete fat molecules. 



The regressive metamorphosis of the parenchyma appears 

 to commence as soon as the gland is no longer required for 

 nursing. In a nursing woman, who died after an illness of 

 three weeks' duration, I found the follicles of the gland already 

 shrunken and condensed, and once more separated from each 



Fig. 209. 



Fig. 209. Acini and stroma from the mammary gland of a nursing 

 Woman who had died after three weeks' illness. System 8. 



other by broad septa of connective tissue containing but little 

 fat ; the acini were small, and no longer contained oil drops, 

 whilst the epithelial cells were in some parts collected into 

 irregular heaps, and in others were scattered over the walls ; 

 the ducts, however, were everywhere permeable to injection, 

 even to their ultimate ramifications. The larger ones con- 

 tained a tenacious brownish material intermingled with fat 

 molecules. The mammary gland of a Bitch presented precisely 

 the same appearances three weeks after delivery. 



I have found similar conditions of the parenchyma of the 

 gland in a healthy female who had had no child for a long 

 time previously, and they must therefore be regarded as 

 representing the inactive state of the organ. At the same 

 time it is quite possible that the regressive metamorphosis 



* Wiener Academ. Berichte, Band liii. ; Abtheil ii., p. 184. 



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