364 TEXT-BOOK OF BACTERIOLOGY. 



also almost regularly in butter. It thrives both at ordinary and 

 breeding- temperatures and is easily stained by the anilin colors. 



On the gelatin plate the colonies appear as neat, white stars, 

 growing 1 rather rapidly, advancing to the surface, and spreading 

 there as flat, white, dry masses. 



The medium is not liquefied. Under the microscope there are 

 seen glassy, greatly ramified hyphag, radiating from the middle of 

 the colony in all directions. 



In the test-tube their growth is found along the entire inocula- 

 tion line, particularly on the surface of the gelatin. 



Here too, the ramified network of the vigorously developed 

 fungus-lawn is seen again. The oidium thrives in milk without 

 causing striking transformations. 



TRICHOPHYTON TONSURANS AND ACHORION SCHCENLEINII. 



The investigations of Grawitz, Quincke, and others have given 

 detailed information regarding favus and herpes tonsurans. 



The regular appearance of thread-shaped structures had been 

 demonstrated long before in the scaly aggregations produced 

 by these two skin diseases. The fungus of favus, the Achorion 

 Schonleinii, and that of herpes, the Trichophyton tonsurans, were 

 the first recognized vegetable parasites of man. Grawitz succeeded 

 not only in cultivating them outside the body, with the aid of more 

 recent methods, but also in demonstrating beyond doubt their 

 causative significance by the successful reproduction of skin dis- 

 eases on man from artificial cultures. 



On microscopic examination both micro-organisms appear as 

 pretty well ramified, flat, filamentous fungi with clearly-articulated 

 hyphae. These are frequently strangely twisted in favus and 

 distinguished by completely rectangular ramifications. Both fungi 

 are destitute of special generative organs. A degeneration of the 

 mycelium into small, roundish members, arranged like " rolls," may 

 sometimes be observed, under certain conditions, and best on blood- 

 serum at 30 C.; they are characterized as conidia. The mycelium 

 generally remains absolutely sterile on gelatin and agar. 



The favus and herpes fungi thrive at ordinary temperature, best 

 at about 30 C. The differences appearing between them in the 

 course of development on gelatin or agar are, indeed, not very evi- 

 dent; but a direct comparison between cultures will suffice for differ- 

 entiation. 



On the plate they develop pretty rapidly, the fungus of herpes 

 tonsurans more so than that of favus. The colonies are of a chalky- 

 white color, star-shaped, and lumpy in the centre. They liquefy gel- 

 atin quickly and extensively. 



