On Trichophyton tonsurans (the Fungus of Ringworm). 243 



glass containing it might be placed for several days in the incubator 

 without the development of adventitious fungi. 



It follows from the facts recorded in this table that although the 

 method may be relied on for the cultivation of ringworm fungus, it 

 cannot be considered certain. 



I am not able to account for the failures recorded in experiments 

 1, 2, 7, and 12, but they did not surprise me. Simultaneously with 

 the experiments on trichophyton I had made a number of cultiva- 

 tions of the common fungi found in our houses, and had learned how 

 delicate are the conditions of growth to which they are all subject. 

 One of the most important of these conditions is the requisite degree 

 of moisture, which must be neither in deficiency nor excess. The 

 failures recorded in these experiments may possibly have been due to 

 the hairs having become too much immersed, or the spores themselves 

 may have been incapable of germination from changes effected in 

 them by inflammatory exudation around the hair follicles before they 

 were extracted. 



The growth observed consisted in a development of mycelium from 

 spores, and in the formation of spores within the mycelium, as is por- 

 trayed in the drawings in the plate. No organs of fructification were 

 observed. 



Two experiments were made with ringworm hairs which had been 

 sunk in water. In one case the length of time of the immersion is not 

 noted ; in the other the hairs were immersed six days. In neither 

 case did trichophyton grow when an attempt at cultivation on 

 vitreous humour was made. Considering the uncertainty of vitreous 

 humour cultivations, these two experiments have only a very limited 

 value, but, so far as they go, they support the inferences which follow 

 from other experiments made in the same direction. The hairs in 

 which trichophyton grew were all freshly extracted, but one expe- 

 riment was made with two hairs, kept dry in a box for thirteen days. 

 The spores were very numerous in these hairs ; only one appearance of 

 growing mycelium was observed, a spore having sprouted on the side 

 of the hair. There were, on the other hand, some similar experiments 

 with negative results. Four cultivations were tried with hairs which 

 had been kept eleven days, and three with hairs which had been kept 

 twenty-two days ; in all of them the spores remained unchanged. 



The value of these experiments is, on account of the uncertainty of 

 the cultivations, not very great, but it may be well to put them on 

 record. The same remark applies to experiments made with hairs 

 taken from patches which were under treatment. The vitality of 

 trichophyton is destroyed as a result of many varieties of treatment, the 

 essential feature in all of which is that they produce inflammation of 

 the skin. As soon, therefore, as I had determined that the spores in 

 untreated hairs could be grown in a fairly large proportion of the 



