398 MOEBID ANATOMY OF THE SKIN. 



main body of the tumour is really situated ; it consists of a pad 

 of sweat-glands, from three to four lines in thickness, and of 

 corresponding Avidth. Each single gland may attain to the 

 diameter of one line ; the adipose tissue seems to be partly 

 pushed aside, while the bands of connective tissue between the 

 individual glands are thickened. 



The occurrence of small cysts, full of clear mucus, must be 

 regarded as a sign of retrograde metamorphosis. They originate 

 in the total liquefaction of single glands, and occupy exactly 

 the same space. 



0. Heteroplastic Tumours. — Lupus. 



§ 342. The undoubted participation of the hair-sacs and 

 sebaceous glands in the genesis of epithelial cancer was satisfac- 

 torily proved in § 166. The hair-sacs and sebaceous glands 

 were shown to behave just like all other protrusions of the epi- 

 dermis into the cutis ; like the sudoriparous glands, and the 

 downward processes of the rete Malpighii which occupy the 

 interpapillary furrows. There exists, however, a true adenoma 

 of the sebaceous and sudoriparous glands, a tumour which, in 

 common with all adenomata, is closely related to epithelial can- 

 cer, but Y/hich differs from it, like ail other adenomata, partly 

 in its structure, partly by its more local and ametastatic cha- 

 racter : I refer to Lupus. 



§ 343. If my views of lupoid growth should seem to be 

 more in accordance with the older than with the more recent 

 observations on the subject, this is probably due to the great 

 reluctance of recent authors to see anything peculiar in lupus, 

 any departure from the common type of inflammatory growth. 

 In reality the lupoid tubercles are so characteristic, not only in 

 their mode of origin, but in their structure also, that I readily 

 pledge myself to recognise lupus, quite as certainly as cancer, by 

 microscopic analysis alone. It is true that the cells of the lupoid 

 tubercle are, on the whole, of small size and round, that they are 

 closely packed, and held together by a mucoid cement ; so that 

 if it were desired to find a name foi* the tissue of which they 

 consist, that of embryonic tissue might well he chosen as the 

 fittest. But ought we on that account to neglect the manifold 

 variety of internal stinicture, and the very singular mode of 

 origin, of this embryonic tissue ? 



