212 GENERAL BIOLOGY 



but it may invade the circulation and cause lesions in other parts of the 

 body. 



"The blastomyces occur in human tissues only in the blastomycetoid 

 form, that is, as small round bodies with granular protoplasm, and with 

 thick hyaline capsules. They multiply by budding only. In cultures 

 they may develop mycelia or grow by budding, or in both ways. They 

 may be numerous in the lesions which they produce, or few and hard 

 to find." 



They produce a fairly strong toxin. 



Aspergillus fumigatus (Fig. 103) is an example of the pathogenic 

 ascomycetes. It is a fungus widely distributed, usually as a harmless 

 parasite, having been found in the auditary canal, nose, and throat. 



In birds, in cattle, more rarely in dogs, Aspergillus may cause lesions 

 of the lungs, resembling tuberculosis, and there have been of late years 

 a good many cases reported in man, particularly pigeon keepers and hair 

 sorters. "In the majority of cases the infection is secondary to some 

 long-standing affection of the lungs," though it also causes a primary 

 lesion resembling broncho-pneumonia, usually quite serious. The patient 

 coughs up a grayish brown mass the size of a bean made up entirely of 

 mycelium and spores. 



Oidiomycosis (granuloma coccidioides) is the term applied to the 

 lesions produced by an Oidium variously named in the past immities, 

 coccydioides, etc., but not yet definitely classified by the botanists. In- 

 fection with this organism is rare and is confined almost exclusively to 

 California. The disease is practically fatal. 



The oidium occurs in human lesions in the form of spherical bodies 

 which may reach a size of thirty microns. They consist of an irregularly 

 staining mass of protoplasm enclosed within a double contoured capsule 

 which is occasionaMy covered with prick 1 es, or even long spines. The 

 organisms multiply in tissues only by endosporulation, never budding. 

 The spores may number as high as a hundred or more. They are lib- 

 erated by the bursting of the capsule. The number of parasites in the 

 lesions varies. They may be many or few and hard to find. In cultures 

 the oidium grows as long septate branching hyphae. In time, spores 

 develop in the ends of the hyphae and are infectious if inoculated in ani- 

 mals; the hyphae themselves are not. 



The lesions produced by Oidium often bear a close resemblance to 

 those caused by the tubercle bacillus, and have probably been mistaken 

 for them more than once on histologic examination. If the organisms 

 are few in number, a. cheesy region may be formed, and if numerous, 

 even abscesses and ulcers. 



Blood and lymph streams seem to carry the organism so that it is 

 widely distributed. It is as likely to be found primarily within, as on 

 the skin of the body. 



