230 SPECIAL HISTOLOGY. 



soon become secreting glands. The fatty cells of the newly- 

 formed glands invariably contain many fat-globules, never a 

 single large drop ; nuclei also occur in them, as in the pale 

 cells which surround them. 



The further development of the sebaceous glands depends on 

 the outgrowth of the external fatless cells of the originally simple 

 tubular gland, into solid processes, which by degrees become 

 changed into glandular vesicles, in the same way as the first 

 rudiments. By repeated budding of the primitive or secondary 

 glandular vesicles, the larger clusters are formed, and from 

 them the most complicated forms which are met with. The 

 so-called glandular rosettes proceed, very often, from a single 

 rudiment, which, growing rapidly, surrounds the hair-sac on 

 all sides ; at other times, however, from two or more primary 

 processes of the outer root-sheath. In the seven months' foetus, 

 most of the glands are simple pedunculated follicles of 

 004 — 0-06"' in length, and 0-02 — 0-03'" in breadth, which are 

 appended, singly or in pairs, to the hair-sacs ; in the ear alone, 

 do four or five glands of the simplest kind surround a sac, and 

 form rosettes of not more than 0'06'" in diameter ; in the nose, 

 simple clusters of at most 0-1'" are presented. In the new-born 

 infant, instead of the simple follicles, simple racemose-glands are 

 found in all the above-mentioned situations, one, or more rarely 

 two, to a sac O'l — 0-12'" in length, and only O04 — 006'" in 

 breadth; on the chest, the glands are rosette-like, also on the ear, 

 temple, nose, nipple, labia major a, and scrotum, where they 

 measure - l'", in the last four places even 0-4"' and more. From 

 these data, it results, that after birth an increase in size takes 

 place in most of the glands, and assuredly in the same manner 

 as during the foetal period, a view which is favoured by the 

 occasional occurrence of pale solid glandular lobules, even in 

 the adult ; certain glands arise only after birth, viz. those of the 

 labia minora. 



[Sebaceous glands also occur in abnormal localities ; thus 

 Kohlrausch (Mull. 'Arch./ 1843, p. 365), observed them in 

 an ovarian cyst, and Von Barensprung (1. c, p. 104) in a subcu- 

 taneous cystic tumour of the brow; in both places they were 

 connected with hair-sacs, whence it may, perhaps, be concluded, 

 that they arc very frequently to be found in cysts which contain 



