264 An Introduction to Medical Mi/cologtj 



(e) Nodular organ.— This is an enlargement consisting of closely 

 twisted hyphae. It may be formed by side branches twining around the 

 main stem or by different filaments. This is seen in M. fnlvum and in T. 

 gypseum. 



(f) Favic chandeliers.— These forms, which resemble reindeer horns, 

 are seen only in A. schoenleini and are usually in profusion. 



(g) Spirals.— Corkscrew-like turns of mycelium are seen particularly in 

 the older fluffy portions of T. gypseum. They are more readily demonstrated 

 on corn meal agar than on dextrose agar. 



(h) Arthrospores.— A modification of the hyphae, with thickening of the 

 walls in short segments, these forms may occur singly or in series. 



2. REPRODUCTIVE FORMS 



Reproduction occurs by asexual spores. These are classed as macroconidia 

 or as microconidia, according to their size. 



(a) Macroconidia. 



(1) Fuseaux (pleuriseptate bundles, spindle spores) .—These are oat- 

 shaped spores which may be connected with mycelium or may be free, 

 since they are readily detached. They may taper at both ends, as in M. 

 lanosum, or one end may be blunt, as in E. inguinale. In some of the Tricho- 

 phyta they are usually observed while attached to mycelium. As a rule 

 they are septate when fully developed; sometimes the partitions are incom- 

 plete, if the specimen is immature. Some workers classify a dermatophyte 

 according to the length of the fuseaux. It is our opinion that, in part at least, 

 the length of the fuseaux may depend on the nutritional content of the 

 medium. 



(2) Chlamydospores — These large, thick-walled spores are observed 

 along the course of a hypha, at its terminus or on a lateral branch. They 

 may be seen in most old growths, particularly in A. schoenleini or M. al- 

 bicans, and in the old parts of the colony of E. inguinale. Evidence indi- 

 cates that chlamydospores are of vegetative function and perhaps should 

 more logically be considered with the preceding group (vegetative forms). 



(b) Microconidia (aleurospores).— 1. The small round or oval spores 

 may be seen free, occurring singly or in grapelike clusters ( grappes ) . 



2. The small spores may be seen in the substance of the mycelium and 

 are then called arthrospores. 



3. If the spores are directly attached to mycelium or to short stocks, the 

 resulting structures may be referred to as hyphae sporiferae (thyrsi sporif- 

 eri). Sometimes the mycelium bearing spores in this manner is of smaller 

 caliber than sterile mycelium in the same field or from the same colony. 



