MOLDS 



273 



the sterigmata. From these other sterigmata may be produced, 

 at the end of which a single chain of constricted, bead-like spores 

 or conidia are formed. Penicillium, the common blue mold, is a 

 familiar example of this group (Fig. 41). 



Molds have claimed attention probably more because of their 

 ability to spoil fruit preserves and other food substances than 

 their tendency to produce disease. Their spores are practically 

 ubiquitous and are more numerous in ordinary air than bacteria. 

 Mold infection of plants, such for example as potato rot, often re- 

 sults in serious economic loss ; other infected plants may if ingested 

 have a disastrous effect upon 

 the body cells. The mold 

 Claviceps purpurea which in- 

 fects rye and other grain has 

 been found to cause a condi- 

 tion of poisoning known as 

 ergotism. 



Fortunately, comparatively 

 few varieties are pathogenic for 

 man. Pigeons are extremely 

 susceptible to the genus Asper- 

 gillus, which gives rise to a 

 form of pseudotuberculosis. A 

 number of cases of the disease have been reported in human 

 beings, especially amongst bird fanciers. A case of mold infection 

 has been reported which at autopsy showed multiple abscesses in 

 the brain, lungs, intestines, and peritoneum, and in all the lesions 

 a species of mucor was found. Eye and ear infections have also 

 been attributed to the same organisms. 



Ringworm. Ringworm is probably the most frequently met 

 with of the diseases due to hypomycetic growth. It is contagious 

 in that it may be communicated from one individual to another 

 or it may be contracted from domestic animals. The disease is 

 caused by at least two different members of the species Tricho- 

 phyta of the fungi imperfecti group, Tinea circinata affecting the 

 body and Tinea tonsurans the head. The fungi are more parasitic 



FIG. 41. Penicillium. 



