THE SKIN. 585 



of the skin, the female breast. In tumors which are either sessile or pedicu- 

 lated molluscum sebaceum the racemose sebaceous glands are sometimes 

 enormously augmented, while the interposed fibrous connective tissue is con- 

 siderably diminished. The epithelium sometimes undergoes a colloid or waxy 

 degeneration, producing large, shining, homogeneous, even stratified bodies, 

 which were thought to be characteristic of molluscum contagiosum. 



Cys tic tumors are secondary formations of adenoma ; they are filled with a 

 serous liquid (serous cyst), with a viscid, colloid, honey-like liquid (meliceris), 

 with a soft, fatty, offensive paste (sebaceous cyst), or with a half -dry, viscid, 

 slightly rancid mass (dermoid cyst). It is very doubtful whether simple 

 obstruction of a duct of a gland will ever give rise to the formation of a cyst, 

 unless previous new formation of epithelium be present, the secondary 

 changes of which give the characteristic properties to the contents of a cyst. 

 Sebaceous cysts, so-called wens, are of frequent occurrence, most commonly in 

 the skin of the scalp and of the face ; they are sometimes present in a very 

 large number. The sebaceous matter is inspissated and infiltrated with lime- 

 salts in cysts termed milium. 



(12) Carcinoma, in all its varieties, flat, nodular, papillary, and plexiform 

 epithelioma, scirrhus, and medullary cancer, is observed in the skin. It is 

 obvious that terms like " alveolar cancer," " epithelial cancer," " plexiform 

 cancer," "epithelioma," etc., are misnomers, as every cancer is necessarily 

 alveolar, and is an epithelioma. We have no reason to confine the name 

 1 ' epithelioma " to cancers of the skin, as in this tissue all varieties occur. 



Flat cancer (so-called " rodent ulcer") is usually seen in the skin of the 

 face, never producing exuberant growths ; but by continuous ulceration it 

 penetrates into the deeper parts and gradually destroys all the tissues. It is 

 the least malignant form of carcinoma, and never produces secondary tumors. 

 Nodular cancer (so-called " epithelioma ") is of frequent occurrence in the 

 skin, usually starting in localities which have been the seat of a long-con- 

 tinued though slight irritation. Papillary cancer (so-called cauliflower 

 cancer) is rare, and appears whenever an exuberant growth of circumscribed 

 portions of the tumor takes place toward the surface. Scirrhus andmedullary 

 carcinoma may grow on any part of the surface of the body, more particu- 

 larly in the female breast. Melanotic carcinoma is rare. In very rapidly 

 growing carcinoma epithelia do not develop, and the tumor remaining in the 

 stage of the so-called medullary or inflammatory infiltration exhibits the feat- 

 ures of globo-myeloma. This is especially marked in the rapidly growing 

 so-called lenticular cancer (cancer a cuirasse) of the skin. 



