142 STUDY AND IDENTIFICATION OF MOULDS 



network between the rete malpighii and the superficial epidermal layers. In cul- 

 tures only mycelial filaments are found, there are no conidia bearing hyphae. 

 The fungus is also called Trichophyton concentricum. 



Epidermophyton cruris. (See Microsporoides minutissimus, page 145) . 

 Under the name "dhobie itch" this fungus affection is probably 

 better known to Europeans than any other tropical skin disease. 



This name dhobie or washerman's itch has been given on account of associating 

 it with the infection of the underclothing while being washed in the pools or streams 

 along with the garments of those who have this skin disease. This, like every other 

 widespread view, has probably some foundation but cannot be verified. It is the 

 eczema marginatum of Hebra. 



This affection is caused by various species of Epidermophyton. This genus 

 differs from Trichophyton in that it never invades the hair or hair follicles. 



The species which have been more frequently reported are Epidermophyton crttris, 

 E. perneti and E. rubrum. The mycelium is about 4 microns broad and the spores 

 about 5 or 6 microns. All of these fungi can be cultured on Sabouraud's maltose 

 agar, growth appearing in about a week, except E. perneti, which grows more rapidly. 



IN THE SUBORDER CARPOASCEES we have to consider the family 

 Perisporiacidae. In this family the asci are completely inclosed by the 

 investing membrane, the perithecium. When this rots the spores are 

 set free. There are three genera of interest, Penicillium, Aspergillus 

 and Sterigmatocystis. 



In Penicillium we have vertical branches with strings of conidia. In Aspergillus 

 these conidia arise from a globular termination of the hypha. 



Penicillium. While Penicillium does at times form perithecia, yet they char- 

 acteristically show chains of spores. The common P. glaucum resembles a hand 

 with terminal beads, more than the hair pencil, from which the name is derived. 



P. crustaceum. Is the common blue-green mould. It has been deemed patho- 

 genic in cases of chronic catarrh of the Eustachian tube and in gastric hyper- 

 acidity. 



P. montoyai. Cause of violet pinta. 



Aspergillus. These have sterigmata carrying chains of spores, these sterigmata 

 being little processes projecting out from the knob-like termination of the aerial 

 hypha (columella). Of the pathogenic Aspergilli we have: 



1. A. fumigatus. This has been considered as the cause of pellagra. A pul- 

 monary mycosis resembling phthisis may be due to this species. 



2. A repens. This has been found in the auditory canal and may produce a 

 false membrane. 



3. A. flavus. This has been found in the discharges of chronic ear diseases. 



4. A. concentricus. Formerly considered as the cause of an important tropical 

 ringworm, tinea imbricata. The scales are dry, like pieces of tissue-paper. 

 There are generally about four rings which do not heal in the center. General 

 appearance is that of watered silk. There are no inflammatory lesions. Com- 



