CHAPTER XLIX. 

 PARASITES OF THE FAMILY MUCORACIDJE. 



Introduction. General methods of examination, cultivation, etc. 

 Section I. The genus Mucor, p. 676. 

 Section II. The genus Lichtheimia, p. 677. 

 Section III. The genus Rhizomucor, p. 678. 

 Section IV. The genus Rhizopus, p. 678. 



THE Mucoracidse, or moulds, 1 are phycomycetous fungi of very wide 

 distribution. 



The Mucoracidse are characterized by a non-septate mycelium carrying 

 spore-bearing hyphse. Under anaerobic conditions, however, the mycelium 

 breaks up into very short septa resembling yeasts. Reproduction takes 

 place either sexually or asexual ly ; in the former case by means of zygospores 

 and in the latter by means of sporangia. 



For a long time the Mucoracidse were regarded as purely saprophytic 

 organisms, but in recent years it has been recognized that they play a part 

 in human and comparative pathology. 



1. Microscopical examination of infected tissues. Prepare films with the 

 pus or other material and stain with methylene blue, thionin, or gentian- 

 violet. It is often better to examine the material fresh. 



For histological purposes, cut sections of the tissue and stain with hsema- 

 toxylin, wash, counterstain with eosin, dehydrate and mount in balsam or 

 dammar resin. 



2. Cultures. The Mucoracidse grow best on an acid medium. They can 

 be easily cultivated on slices of fruit or potato and on pieces of sterile bread. 

 A simple method is to cut a slice of bread into small pieces leaving the crust 

 on one side, and place them in potato tubes with a little water at the bottom, 

 then plug the tube with wool and sterilize at 115-120 C. 



Decoctions made of dried fruit, hay, yeast, or beer-wort, and Nsegeli's, 

 Raulin's or Sabouraud's media either as liquid or after solidification with 

 gelatin, are all useful for growing the species of this family. 



3. Isolation of the fungus. According to Gedoelst the most satisfactory method 

 of getting a pure culture from a single spore is to dip a sporangium into a watch- 

 glass containing a little sterile water. The sporangium bursts immediately and the 

 spores are set free in the water ; leave them in the water to swell for a few hours. 

 Then with a platinum loop take up a drop of the water, spread it on a sterile slide 



1 The term " mould " as generally used is applied somewhat loosely, and includes 

 beside the Mucoracidse a number of fungi belonging to the order of the Ascomycetes. 

 These will be considered later. 



