FUNGI 
217 
For showing the ascogonium, ascogenous hyphae, and the origin 
of the asci, nothing is better than Pyronema. Fix in formalin, acetic 
acid (10 c.c. formalin, 5 c.c. acetic acid, and 85 c.c. water) for 24 
hours or more; wash in water and stain in eosin. Or, fix in the special 
chromo-acetic-osmic solution and stain in iron-alum haematoxylin. 
In either case, use the Venetian turpentine method and tease the 
material so as to obtain instructive views. 
Eurotium. —Eurotium with its conidial stage, Aspergillus , is a 
very common mold found on bread, cheese, decayed and preserved 
fruit, etc. In the conidial stage it is green and in the ascosporic 
stage yellow, reddish yellow, or reddish brown. Aspergillus is 
Fig. 57. — Aspergillus: from material growing on a hectograph pad; fixed in chromo-acetic 
acid, stained in eosin, and mounted in glycerin; A-E, successive stages in development. X375. 
All such material is more satisfactory when mounted in Venetian turpentine. 
almost sure to appear upon bread which is kept moderately moist, 
because the conidia are usually abundant in the atmosphere. If 
the bread be wet with a 10 per cent solution of cane-sugar or with 
grape juice, this stage appears sooner and in greater abundance. 
A temperature of 22° to 30° C. is also a favorable condition. 
The perithecial stage is not found so frequently, but can sometimes 
be secured by examining moldy preserves. The sexual stage has been 
induced. Soak a piece of bread in a 20 per cent solution of grape-sugar 
in grape juice; upon this sow the spores and keep at a temperature of 
about 28° C. After 4 or 5 days, begin to examine. A 40 per cent solution 
of cane-sugar in the juice of prunes is also a good nutrient solution. 
For class use or for permanent preparations it is best to select 
rather young material which shows various stages in development, from 
the swollen end of the hypha to the ripe spore (Fig. 57). Permanent 
preparations of the conidial stage, as shown in Figure 57, and also of the 
coiled twisted filaments which initiate the ascosporic stage, should be 
made by the Venetian turpentine method or by the glycerin method. 
