278 SPECIAL HISTOLOGY. 



or less fat, and originate either in a free cell-formation or from 

 epithelial cells, in a way analogous to that in which the 

 cutaneous sebaceous matter is formed (vid. § 73), by their 

 continued multiplication. These cells, which I would designate 

 milk-cells, break up, so soon as they reach the lactiferous ducts, 

 into their elements, the milk-globules ; the membrane, and for 

 the most part also, the nucleus, disappearing, without a vestige 

 being left, so that the milk, when secreted, usually presents 

 no indication of its mode of origin. At most, there occur in 

 it a very few larger or smaller aggregations of milk-globules, 

 which, from their similarity to those met with in the 

 colostrum, may likewise be termed colostrum-corpuscles. The 

 secretion of the milk, therefore, depends essentially upon a 

 formation of fluid and fat-containing cells in the gland-vesicles, 

 and consequently falls into the category of those secretions into 

 the composition of which morphological elements enter ; above 

 all to the fatty secretions, such as the cutaneous sebaceous 

 matter, in which cells of precisely similar kind occur to those 

 met with in the gland-vesicles of the lacteal glands and in the 

 colostrum. 



In the new-born child, the mammary gland very frequently 

 contains a small quantity of a fluid presenting the external and 

 microscopical characters of milk, the origin of which is probably 

 related to the formation of the glandular ducts. 



[With respect to the colostrum-corpuscles and fat-globules 

 of the colostrum, Bernhardt was the first to prove, that the 

 supposition broached by Nasse and Henle, that these bodies 

 are related to a formation of fat-containing cells in the mam- 

 mary glands, and that the former in their more usual form are 

 nothing but membraneless cells, and the latter oil-drops 

 liberated from cells, is in every respect well founded, although 

 he is inclined to distinguish the formation of the colostrum 

 from the secretion of milk, and to regard the former as a 

 pathological process, as a fatty metamorphosis, by which the old 

 epithelial cells of the gland, previously to the formation of true 

 milk, are evacuated externally, and particularly because, in the 

 true milk-formation, he was unable to perceive any fat-con- 

 taining cells. But since V. Bueren, especially, has found such 

 cells, and consequently the formation of the milk and of the 



