638 



PATHOGENIC MICROORGANISMS 



mata arise. On the ends of these sterigmata spores or conidia develop 

 similar to those developed by penicillium. 



Other forms of sporulation occur within this group. Thus, tubular 

 spore capsules may be formed within the end segments of the hyphse, 

 known as ascospores. In other cases, within a mycelial thread, a 

 swelling may take place into which protoplasm flows from the neighbor- 

 ing cells, at both ends. In this way, an oval spore case is developed 



FIG. 147. MUCOR MUCEDO. Formation of zygospore. 1. Two branches coa- 

 lescing. 2 and 3. Process of conjugation. 4. Ripe zygospore. 5. Germination 

 of zygospore. 6 and 7. Mucor erectus. Azygo sporulation. No two branches 

 meet, but form spores without conjugation. 8 and 9. Mucor tennis. Azygo 

 sporulation. The spores grow out from side branches without sexual union. (1-5 

 after Brefeld; 6-9 after Bainier, from Tavel.) 



within the course of the mycelial thread. This is known as a chlamy- 

 dospore. The segments on each side of the chlamydospore die out 

 and the spore capsule is liberated from the mycelium. 



The classification of the various divisions of the hyphomycetes is a 

 problem requiring much study and great botanical insight, and can 

 hardly be discussed in a general work on bacteriology. 



Upon artificial media, the members of this group aro not at all 

 fastidious, growing easily upon organic matter of all kinds, provided 



