CHAPTER XX 



FUNGI 



Our principal object is to describe methods of making preparations 

 for a study of the morphology and cytology of the fungi. The whole 

 subject of culture media, especially for those which cause disease, has 

 become so specialized that only the trained pathologist could be ex- 

 pected to know just what is the best medium for each particular fungus. 



We shall not attempt to deal with the subject of culture media, but 

 shall simply indicate how a student, not trained in pathology, may 

 secure material for preparations. Professor Kleb's methods make it 

 possible to secure material of many forms in various phases of their 

 life-histories. 



In general, filamentous fungi are treated like the filamentous algae, 

 while the fleshy forms are cut in paraffin. 



PHYCOMYCETES 



Rhizopus (Mucor).— This familiar mold appears with great regu- 

 larity on bread. The following is a sure and rapid method for obtain- 

 ing Rhizopus: Place a glass tumbler in a plate of water, put on the 

 tumbler a sHce of bread which has been exposed to the air for a day, 

 and cover with a glass jar. The bread must not become too wet. 



To obtain a series of stages in the development of the sporangium 

 it is better to use living material. For class work, time the cultures so 

 as to have plenty of sporangia which have not yet begun to turn 



brown. 



For permanent preparations, fix for 2 or 3 days in formalin acetic 

 agi(j — 10 c.c. formalin, 5 c.c. glacial acetic acid, and 85 c.c. water — 

 wash 24 hours in water, and follow the Venetian turpentine method. 

 Stain in aqueous eosin 24 or even 48 hours, treat with 2 per cent acetic 

 acid, changing several times, and then put into glycerin, merely pour- 

 ing off the 2 per cent acetic acid and not rinsing the acid out in water. 

 When washing out the glycerin, do it with alcohol which has about 0.5 

 c.c. of acetic to the 100 c.c. of alcohol, and leave about 1 c.c. of this 

 slightly acid absolute alcohol on the material when you add the 10 per 

 cent Venetian turpentine. 



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