246 



Dr. G. Thin. 



The main conclusions regarding Trichophyton tonsurans which are 

 warranted by the experiments recorded in this paper are that : — 



1 . It is not one of the common fnngi. 



2. It can be cultivated artificially when moistened by vitreous 

 humour. 



3. When covered by vitreous humour it does not grow. 



The second of these formulated statements suggests whether the 

 inability of the fungus to grow in the hairs of the scalp in adults may 

 not be due to the firmer texture of the root-sheaths, and the consequent 

 comparative absence of moisture between the inner root-sheath and the 

 hair. The third explains why the fungus may be destroyed by pro- 

 voking inflammation of the scalp. 



DESCRIPTION OF PLATE 2. 



Figure 1. Cultivation in a cell. (Two days in the incubator.) 

 x 750. 



Figure 2. Cultivation on the surface of vitreous humour in a test-glass, showing the 

 first appearance of spore-formation in the mycelium, 

 x 600. 



Figure 3. Growth on the surface of vitreous huniour in a test-glass, showing an 

 early stage of spore-formation, 

 x 880. 



Figure 4. Spores germinating. Drawn (without the camera) from a preparation in 



a cell the same day in which it had been placed in the incubator. 

 Figure 5. Two days' growth in a cell, 

 x 750. 



Figure 6. Two days' growth in a cell, 

 x 750. 



Figure 7.* A. hair from a cultivation on the surface of vitreous humour in a test- 

 glass. A mass of germinating and sprouting spores on a portion of the 

 internal root-sheath which was attached to the hair is seen at the side 

 of the hair-shaft. Buds and mycelium are sprouting from the sides of 

 the hair. (In order to reduce the size of the drawing the centre of the 

 hair-shaft has been left out.) 

 x 450. 



* No attempt has been made to represent the fungus growth on the upper sur- 

 face of the hair, as it lies in the preparation. The outlines were too much obscured 

 by the thickness of the hair to enable this to be accurately done with the camera. 



