On Trichophyton tonsurans (the Fungus of Ringworm). 235 



The fungus, as at present known, consists of a mycelium and spores, 

 and very little has been determined regarding its nature. Attempts 

 that have been made to cultivate it artificially have led to contra- 

 dictory conclusions. Lowe, in 1850,* was induced to believe that 

 Trichophyton tonsurans is a spore formation of the fungus of favus — a 

 specifically distinct parasitic disease of the skin — and that both are 

 forms of Aspergillus. Neumann, f on the other hand, whilst believing 

 that his cultivation experiments showed that herpes tonsurans and 

 favus are produced by the same fungus, traced it in both diseases to 

 Penicillium glaucum. Dr. Atkinson, J again, was led by his cultivations 

 to believe that the fungus belongs to the Mucors, and is probably 

 Mucor mucedo. 



The reason why the botanical relations of the parasite to the 

 common fungi have been so difficult to determine has been stated by 

 De Bary. " If," he remarks, § speaking of the vegetable parasites of 

 the skin, " the parasites, when removed from the bodies of their hosts, 

 are cultivated in water, sugar solution, &c, the vegetation of their 

 spores is then observed, and after a short time there appears in. the 

 fluids the universalis wide-spread fungi, e.g., Penicillium glaucum, 

 Aspergillus glaucus, or Torula. The latter and the mycelium of Peni- 

 cillium resemble more or less the spores and mycelium of the parasites 

 in question, and, being found in immediate contact with them, it seems 

 as if they had been developed from them in the artificial medium." 



K6bner,|| who endeavoured to solve some of the problems connected 

 with the development of the parasite by clinical experiments, found 

 that Trichophyton tonsurans, when inoculated on the skin, produced 

 only herpes tonsurans, and that he could not produce this disease by 

 inoculation with Penicillium glaucum. 



A strong reason exists, independently of experimental results, for 

 believing that trichophyton is not a form of the common fungi. The 

 facility with which ringworm is communicated from one child to 

 another by contact, or by interchange of caps, shows that the fungus 

 takes root easily on the scalp, whilst, as many a country medical prac- 

 titioner can testify, bareheaded children may be exposed indefinitely 

 to contact with ail the spores with which the atmosphere is pregnant 

 without a single instance of the disease being produced. 



In endeavouring to cultivate Trichophyton tonsurans artificially, it 

 was clear to me that one of the chief difficulties to be overcome was to 



* " Botanical Transactions." Edinburgh.. 1850. 

 f " Lehrbuch der Hautkrankheiten." 2nd edition. 



X " On the Botanical Relations of the Trichophyton tonsurans." " New York 

 Medical Journal," December, 1878. 



§ Hofmeister's " Handbuch der Physiologischea Botanik," Band 2, Abth. 1 , 

 p. 224. 



|| " Klinische und Experimentelle Mittheilungen." Erlangen. 1864 



