FAVUS. 507 



nave developed in the funnel-shaped mouth of the hair-follicle, and 

 have elevated the epidermis around the hair. When the masses of 

 favus are numerous, and as they increase in size, they come into con- 

 tact, coalesce, and finally form a continuous rind of fungi, covering the 

 entire scalp (favits conferlus s. confluent). If, however, the favus- 

 spots are separate and do not encroach upon their neighbors, a very 

 characteristic formation takes place, consisting of round, concave scabs, 

 like crabs'-eyes, the lower convex surface of which lies embedded in a 

 depression in the atrophied cutis, while their upper surface has ele- 

 vated edges with a depressed centre (favus scutiformis). This 

 thick, dry, sulphur-yellow scab consists of a structureless capsule, 

 which adheres very firmly to the thin layer of epidermis beneath it, 

 and of innumerable filaments and spores. As the hair-follicle and hair it- 

 self become overgrown by the fungi, the growth of the hair is impeded ; 

 it loses color, and becomes dry, thin, brittle, and falls out. When 

 favus is situated upon a part of the skin destitute of hair, the mass 

 of spores generally becomes loose after a few weeks and falls off, 

 thus putting an end to the disease. Its course is different upon 

 the hairy scalp. Here, too, the duration of the individual masses of 

 favus is limited, but the scabs adhere longer, and the fungi which they 

 contain infect the parts about them. When finally the scab detaches 

 itself, the pressure which it has exerted upon the skin leaves the latter 

 in a state of atrophy which is never repaired. The hair does not 

 usually grow again upon the former site of the disease, and the pa- 

 pillae which have more especially suffered from the atrophy can only 

 reproduce a thin layer of epidermis ; hence, for the rest of the patient's 

 life, there remain upon his head bald smooth depressed spots, whose 

 edges are often surrounded by more recent crusts of favus. The 

 growth of the fungus, the scratching provoked by it, and the lice by 

 which it is often accompanied, frequently cause eczematous and impe- 

 tiginous inflammation of the scalp. When this complication occurs, 

 besides the favus-crusts, there are other scabs, the desiccated product 

 of the eczematous exudation. These scabs are easily distinguishable 

 from those of favus. Under the latter, the skin, though depressed, 13 

 always covered by a thin layer of epidermis ; under the former, we 

 always find an excoriation. 3 



TREATMENT. Difficult as it is artificially to induce the favus-spores 

 to grow, it is equally difficult to destroy them when once established 

 upon the hairy scalp, and to arrest then* further ravages. We have 

 said that the fungi form within the hair-follicles and upon the hairs 

 themselves ; hence, not only must all the crusts be removed, but all 

 hairs upon the diseased surface must likewise be extracted. The for- 

 mer object is best attained by saturating the crusts with grease, until 



