582 THE SKIN. 



tids, with a fully developed reticulum of living matter the pus-corpuscles. 

 The principal sources of pus-corpuscles, therefore, are the epithelia themselves, 

 the endogenous formation. (See page 419, fig. 176.) How many of the 

 pus-corpuscles appear through an immigration from below, from the inflamed 

 connective tissue or from the blood-vessels, nobody can tell. The immigra- 

 tion is a sensible hypothesis only, without direct proof or foundation, while 

 the endogenous formation can be directly traced in all its stages. The pus- 

 corpuscles are coarsely granular, viz. : are supplied with a large amount of 

 living matter at the points of intersection of the living reticulum in persons 

 of a good, strong constitution; on the contrary, they are finely granular that 

 is, scantily provided with living matter in persons of a weak, so-called scrofu- 

 lous or tuberculous, constitution, or in persons debilitated by any acute or 

 chronic disease. In the former instance the pus is thick and yellow, in the 

 latter instance watery, serous, and pale. The subjacent connective tissue, as 

 a rule, does not advance beyond its reduction into a medullary tissue. In 

 some cases, however, the newly appeared and newly formed medullary cor- 

 puscles, which produce the infiltration of the derma to a varying depth, are 

 also torn asunder, and thus represent pus-corpuscles, which, commingling with 

 the pus which has sprung from the epithelia, take part in the formation of the 

 abscess. 



This stage of inflammation is known by the term pustular stage of small-pox, 

 and represents the typical termination of the whole process. The pustule 

 either bursts or its contents dry and produce the crust. So long as the 

 inflamed derma remains in the condition of medullary tissue, so long as 

 the medullary or inflammatory elements remain connected with each other, 

 the new formation of a glue-yielding basis-substance in the shape of bundles 

 of fibrous connective tissue will be accomplished, without the formation of a 

 scar. If, on the contrary, a part of the connective tissue has been trans- 

 formed into pus, and thus completely destroyed, the result will be a cicatrix. 

 Mere epithelial suppuration heals without the formation of a scar, while sup- 

 puration of the connective tissue always produces a mark. The pigmentation 

 of the skin, so common after small-pox, is due to the imbibition of the color- 

 ing matter of the red blood-corpuscles ; or by changes of the directly extrava- 

 sated red blood-corpuscles, both in the rete mucosum and the derma. Such 

 extravasations occur in all severe cases of small-pox in the highest degree, 

 of course, in hsemorrhagic small-pox. 



My observations on inflamed portions of skin have led me to the following 

 conclusions : 



(1) In epithelium, the first step of the inflammatory process consists in an 

 increase of the living matter, both in. the plastids and between them; the 

 former produces the coarse granulation of the epithelia, the latter the thick- 

 ening of the so-called " thorns" in the cement-substance. Any particle of 

 living matter, both in the epithelia and between them, through a continuous 

 growth, may lead to a new formation of the epithelial elements, with termina- 

 tion in hyperplasia of epithelium (psoriasis, squamous eczema, horny forma- 

 tions, etc.). 



(2) In connective tissue, the first manifestation of the inflammatory 

 process is the dissolution of the basis-substance and re-appearance of the 

 bioplasson condition ; by this process and the new formation of medullary 

 elements, which may start from any particle of living matter, the inflamma- 

 tory infiltration is established. The sum total of the inflammatory corpuscles, 





