454 



MEDICAL MYCOLOGY 



or of the series connected Avith increasing specialization for parasitism, we find 

 that as the closterospore is less highly developed (Fig. 83), the so-called 

 chlamydospores increase in numbers and each (containing 2-5 nuclei) func- 

 tions as a single cell of a closterospore. 



The aleurospore seems homologous in function to the conidium of the 

 Gymnoascaceae, although we can trace a degeneration in its formation from 

 a well-defined spore borne on a denticulation, to a spore which might equally 

 well be an initial of a branch transformed into a resting spore (Fig. 84). 

 Sometimes the sporiferous hypha is partially differentiated into a thyrsiform 

 conidiophore, while in other species there seems to be no differentiation from 

 the vegetative hyphae. Or perhaps the aleurospore represents a very degen- 

 erate ascus where meiosis has failed. The form of the thyrsus resembles the 



Fig. 84. — Aleurospores. 1, Megatrichophyton roseum var. vinosum; t, Ectotrichophyton 

 lacticolor; S, Acliorion muris ; Ji, Trichophyton tonsurans; 5, Endodermophyton tropicale ; 6", 

 Favotrichophyton violaceum; 7, Achorion Schoenleini; 8, Favotrichophyton ochraceutn; 9, Acla- 

 dium Castellanii; 10, Microsporum ferrugineum ; 11, 12, Ectotrichophyton mentagrophytes. 

 (After Ota & Langeron 1923.) 



ascogenous hyphae of the Gymnoascaceae ; the aleurospore is always uninucleate ; 

 on germination its nucleus divides only two or three times before the daughter 

 nuclei migrate into the germ tube. Only uni- or binucleate secondary mycelium 

 develops, instead of the multinucleate mycelium, with nuclear division far in 

 advance of septal formation, as in the primary mycelium. 



In this connection it may also be noted that in Nannizzi's experiments 

 Ectotrichophyton mentagrophytes (Trichophyton gypseum asteroides), E. men- 

 tagrophytes var. radiolatum (T. radiolatum), E. felineum (T. felineum) and 

 E. felineum var. denticulatum (T. denticulatum) produced structures resembling 

 the fructifications of the Gymnoascaceae where aleurospores were found in- 

 stead of asei. These structures are also similar to the pycnia of Ctenomyces 



