CHAPTER XVII 

 FUNGI 



In general, the filamentous fungi are treated like the filamentous 

 algae, while the fleshy forms are cut in paraffin. Bacteriological 

 methods are used in making test-tube and Petri dish cultures. 

 Professor Klebs's investigations make it easy to secure material of 

 many forms in various phases of their life histories. 



PHYCOMYCETES 



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

 regularity on bread. The following is a sure and rapid method for 

 obtaining Mucor: Place a glass tumbler in a plate of water, put on 

 the tumbler a slice 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 a plenty of sporangia which have not yet begun to 

 turn brown. 



If permanent preparations are wanted, they are easily made. Fix 

 for at least 24 hours in 5 to 10 per cent formalin; wash \ hour 

 in water, and then follow the Venetian turpentine method. Eosin, 

 Delafield's haematoxylin, or the Magdala red and anilin blue will 

 prove satisfactory. 



The finer details of the sporangium can be seen only in thin 

 sections. Mucor is the most easily obtained material to illustrate 

 the progressive cleavage of cytoplasm by vacuoles. For this pur- 

 pose, fix in chromo-acetic acid (1 g. chromic acid and 2 c.c. glacial 

 acetic acid to 200 c.c. of water), with or without the addition of 

 about 2 c.c. of osmic acid to 50 c.c. of this solution. Cut 2 to 5 JJL 

 in thickness and stain in safranin, gentian-violet, orange. 



The zygosporic stage in the life history is rarely met in nature 

 or in cultures, but when once secured it may be propagated indefi- 



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