FUNGI IMPERFECTI— FAVUS 295 



of the fungus. This fungus has been cultivated in ordinary agar or by Krai's 

 method. It grows well at higher temperatures, and in 24-48 hours the fungus 

 threads appear. The spores germinate at 35° C. in 14 hours, and in 24 hours 

 a fine mycelium appears in the air. In nutrient media likq potato, gelatin and 

 agar, chlamydospores and yellowish bodies appear. The organism requires 

 higher temperatures for its best development, the optimum is 35° C. The 

 organism from some of the lower animals, however, grows at lower temper- 

 atures. 



According to Walsch the best development of the fungus in the hair is near 

 the upper end of the root, from here it extends upward or downward; the' 

 mycelium may be exfollicular or on the surface of the hair. 



The favus of man does not differ especially from that of animals except 

 in color, and in the shorter duration of the disease in animals. 



Distribution. Widely distributed in Europe and North America, but,, 

 according to Hyde and Montgomery, less common in the United States, Austria,, 

 and England, than in France, Scotland and Poland. 



Pathogenic properties. This form of dermatomycosis known as Favus was 

 discovered by Schonlein in 1839. In the middle ages, it was known as Tinea,, 

 meaning a moth or worm. Previous to the discovery of the organism by 

 Schonlein, various troubles were classed as favus. 



Heusinger suspected the fungus nature of the disease as early as 1826. 

 Remak, in 1845, cultivated the organism upon apple and transmitted it to his 

 arm. He named the fungus Achorion Schonleinii and in medical literature it 

 is frequently referred to by this name. 



The favus organism of mice was discovered in 1850 by Bennett and recog- 

 nized by subsequent investigators like Schroeder and Simon. Favus of cats,, 

 guinea pigs, and dogs was recognized by Saint Cyr. Gerlach found it in birds, 

 and Gruby, three years after the discovery of the organism by Schonlein, found 

 it in hairs on the heads of children and the hairs of the beard. In recent times, 

 various views have been expressed with reference to the nature of favus and' 

 trichophytosis, it being held that these diseases are produced by different fungi. 

 Pick in 1887, Walsch in 1896, and others considered the fungus to be poly- 

 morphic. Quincke distinguished three varieties but pathologists are not agreed' 

 on this point. Plant, in his discussion of the parasitic fungi, divides them into 

 the following groups : the Favus and the Trichophytic groups. According to 

 this view, the favus of man and that of animals are regarded as distinct fungi. 

 The disease in man generally appears where hairs occw, but may appear 

 also in other parts of the body as the eyes, nails, etc., seldom becoming general. 

 Favus of the nails is called Favus onychomycosis. In lower animals the disease 

 may occur on the head, nose, ears, back and, more frequently, is generalized. 

 Formerly this disease was common among the poorer classes. Today, it is 

 not common in France, Holland, Scandinavia, Germany, England, Switzerland, 

 Japan or America; on the other hand, it is rather frequent in Russia, Scotland, 

 Italy, Spain, Asia, Austria and Egypt, young individuals being more suscep- 

 tible to it than are older persons, probably acquiring the disease by contact. 

 The disease is spread through spores of the fungus. The mycelium itself, ac- 

 cording to Grawitz, is not capable of spreading the disease of animals. In 

 man it is recognized by the development of minute yellowish or reddish points; 

 delicate vescicles may surround these spots. Later, the fungus may develop a 



