THE SKIN. 583 



which remain united with each other by means of delicate offshoots, represents 

 an embryonal or medullary tissue. If the new formation of medullary cor- 

 puscles be scanty, resolution is accomplished by new formation of the basis- 

 substance (erythema, erysipelas, etc.). If, on the contrary, the new formation 

 of medullary elements be profuse, a new formation of connective tissue will 

 result (hyperplasia, scleroderma, elephantiasis, etc.). 



(3) Plastic (formative) inflammation may be accompanied by the accu- 

 mulation of a larger amount of a serous or albuminous exudation in the 

 epithelial layer (miliaria, sudamina, herpes), or in the connective tissue of 

 the derma (urticaria). In both instances complete resolution will ensue. 



(4) Suppuration in the epithelial layer of the rete mucosum is produced 

 by an accumulation of an albuminous or fibrinous exudation, by which a 

 number of epithelia are destroyed, and by new formation of pus-corpuscles 

 from the living matter of the epithelia themselves. Epithelial suppuration 

 heals without the formation of a cicatrix (eczema madidans et pustulosum, 

 impetigo, pemphigus, variola). 



(5) Suppuration in the connective tissue of the derma results from the 

 breaking apart of the newly formed medullary corpuscles, which, being sus- 

 pended in an albuminous or fibrinous exudation, now represent pus-corpus- 

 cles. Pus is a product of the inflamed connective tissue itself, and is always 

 a result of a destruction of this tissue. Suppuration of the derma invariably 

 heals through cicatrization (abscess, furuncle, acne, ecthyma, variola). 



Tumors of the SMn.* (1) Myxomatous or mucoid tumors are composed of a 

 delicate fibrous reticulum, the meshes of which contain a jelly-like basis- 

 substance and plastids varying greatly in size. They are frequently found 

 on the skin as soft, jelly-like, sessile, or pediculated protrusions. They are 

 often supplied with a large quantity of blood-vessels, and are then soft 

 tumors, of a dark red color, the " myxo-angioma." Myxomatous tumors, 

 having the structure of the thyroid body and called " lymph-adenoma" or 

 "lymphoma," are very rare. They may occur in the subcutaneous tissue 

 of the neck, but have no connection with the thyroid body itself. 



(2) Fibrous tumors in all their varieties (see page 483), and also the com- 

 bination of fibrous with myxomatous connective tissue, so called "myxo- 

 fibroma," being, as a rule, scantily supplied with blood-vessels, are common 

 tumors of the skin, appearing as hard, sessile nodules and nodes (hard 

 fibroma), or as pedunculated tumors, sometimes scattered over the entire 

 tegumentary surface (fibroma molluscum) ; as tumors of varying size, and 

 softer consistence (soft or myxo-fibroma) ; as pigmented flat elevations of the 

 skin (ncKvi) ; or as scar-like, irregularly branching, sometimes freely vas- 

 cularized new formation (Jceloid). The peculiarity of these entirely benign 

 tumors is that after extirpation they sometimes recur, and even the scar, 

 after the removal of a fibroma, may assume the features of a keloid. 



(3) Chondroma and (4) Osteoma, do not occur on the skin. 



(5) Myeloma (sarcoma), in its two principal varieties viz. : globo-mye- 

 loma and spindle-myeloma is of somewhat infrequent occurrence; in the 

 derma it usually appears as fibro-myeloma ; rarely as a pigmented melanotic 

 myeloma. Such tumors originate as nodules of the skin, sometimes accom- 

 panied with inflammatory symptoms, and their malignancy is proved by their 



* A paper read before the American Dermatological Association, at their meeting in New- 

 port, B. I., August 31, 1880. Printed in abstract in " Archives of Dermatology," Philadel- 

 phia, October, 1880. 



