382 MORBID ANATOMY OP THE SKIN. 



cause of the lympliangiectasis, by hindering the circulation of 

 the lymph in the substance of the corium proper. 



y. Heteroplastic Growths, 



§ 322. A reference to the discussions embodied in the 

 Oeneral Part of the present treatise will allow us to be very 

 brief in speaking of those heteroplastic growths to which the 

 skin is liable. This applies more particularly to myxomatous 

 and lipomatous tumours, which originate by preference in the 

 subcutaneous areolar tissue ; also to cavernous growths, to the 

 sarcomata and fibroid tumours, which may occasionally be met 

 with in the subcutaneous tissue. 



The various kinds of Carcinoma usually affect the skin only 

 in a secondary manner ; for we either find a cancer of deeper 

 parts, e.g. of a lymphatic gland, a muscle, or a bone, making 

 its way outwards to the skin by continuity of tissue, or else a 

 true metastatic deposit in the skin, formed during the later 

 stages of carcinomatosi.^;. In the latter case, the disease usually 

 assumes the form of flattened tubera vaiying in size from a pea 

 to a hazel-nut, mainly confined to the skin of the trunk. The 

 name of ^^ ivory cancer of the skin" (Alihert), or '^cancer en 

 cuirasse " {Cruveilhier), is applied to a scirrhous or colloid cancer 

 of the mammary gland, when this extends in small but closely 

 aorcrreaated nodules over the entire skin of the front of the chest, 

 converting it into a tough, white, translucent, smooth, and lus- 

 trous rind, as hard as a board. 



§ 323. The specific products of leprosy, of syphilis, and (sup- 

 posing my own view to be wrong)* of lupus, form, in respect of 

 their histology, a natural group, which, as we have already had 

 occasion to see, is distinguished by its peculiar hybrid position 

 on the border-land between inflammation and tumours. The 

 acme of the tissue-development, the point at which it culmi- 

 nates, is the production of an embiyonic tissue, which so closely 

 resembles the familiar inflammatory proliferation of connective 

 tissue, that Virchow has actually given it the name of granula- 

 tion-tissue, and has embodied the whole in a class of " granu- 



* Cf. § 317, last sentence. 



