220 SPECIAL HISTOLOGY. 



contain fat, and which now soon open into the hair-sac. In the fifth 

 month, therefore, the secretion has already begun in many places, and 

 in the sixth it is everywhere established. At the same time, however, 

 it is to be observed that, together with the original glands, which occur, 

 one or two together to each sac, in the sixth month, new rudiments are 

 produced, which generally lie deeper, and taking on the same course as 

 that which has been described, 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 out- 

 growth 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 rudi- 

 ment, 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 0-04-0-06 of a line in length, and 0-02-0-03 of 

 a line 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 sur- 

 round a sac, and form rosettes of not more than 0*06 of a line in dia- 

 meter ; in the nose, simple clusters of at most 0-1 of a line 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 0-1-0-12 of a line in length, and only 0-04-0-06 of 

 a line in breadth ; on the chest, the glands are rosette-like, also on the 

 ear, temple, nose, nipple, labia majora, and scrotum, where they mea- 

 sure 0-1, in the last four places even 0-4 of a line 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 favored 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 subcutaneous cystic tumor of the 

 brow; in both places they were connected with hair-sacs, whence it may, 

 perhaps, be concluded, that they are very frequently to be found in 

 cysts which contain hair. In fact I met with very beautiful sebaceous 

 glands, with a considerable amount of sebaceous matter, in the walls of 



