346 MORBID ANATOMY OP THE SKIN. 



which tends to undergo further decomposition and putrefaction 

 so soon as it is supplied with enough moisture for the purpose. 

 If we reflect that the papillary body in its catarrhal state yields 

 enough flviid to set this i:)utrefactive process going, and that 

 decomposing and therefore irritating matters are being con- 

 tinually produced on the under surface of the scab, the surface 

 which is turned towards the papillary body, we cannot but con- 

 clude, and our conclusion will be justified by clinical experience, 

 that so far from exerting any salutaiy influence, the scab is 

 positively a hindrance to the reparative j^rocess ; peculiarly 

 favourable conditions, such as a very rapid recession of the 

 hypersemia, a very complete degree of desiccation, &c., being 

 needed, to allow of the catarrhal process healing underneath 

 the scab. 



The denuded surface is clothed in just the same way as it is 

 after the desiccation of a vesicle. I have indeed observed that 

 concentrically-laminated globes, the so-called '^pearly nodules," 

 are exceptionally frequent in the new cuticle produced under 

 such circumstances ; this hov>^ever is undoubtedly owing to tem- 

 porary irregailarities in the process of stratification. 



§ 293. The case is dift'erent when we have to do with an 

 eruption which, for other reasons, has no tendency to get well ; 

 when the vesicles and pustules are merely the acute beginnings 

 of a chronic catarrh. For instance, some forms of eczema 

 aff*ecting the legs are essentially due, not to external irritation, 

 but to chronic disturbances of the circulation, to venous hyper- 

 semia and phlebectasy. 



These afford us our best opportunities for observing chvonic 

 catarrh of the skin. Its phenomena depend on a clu'onicity and 

 increasing intensity of the hyperemia of the papillary body. 

 This causes in the first place, and directly, the continuance of 

 secretion from the affected patch. Large quantities of transuded 

 fluid force their way to the surface ; the purulent character of 

 this secretion standing in an inverse ratio to its volume, since 

 the rate of production of the pus-corpuscles remains constant, 

 while the transudation increases considerably in amount. Finally 

 we get a fluid which is almost clear, and very rich in salts ajid 

 albumen; its enormous quantity sets all bandages at defiance 

 (" Salt Flux"). The skin undergoes a progressive alteration 

 which may briefly be described as an inflammatory hyper- 



