FUNGI 
215 
secure only old fertilized eggs, with very few of the younger stages. 
The oosporic phase of Albugo bliti is easily recognized on Amaranthus, 
especially on A. retroflexus , where the oospores may be seen with the 
naked eye by holding the leaf up to the light. The oospores usually 
occur in more or less circular patches upon the leaf. When they 
occur among the floral structures, there is often a slight reddish colora¬ 
tion. Unfortunately for the collector, it is very seldom that any 
red coloration in Amaranthus is due to the desired material. 
The oosporic stage of Albugo Ipomeae , on the morning-glory, 
causes extreme distortion of the stem. For sections, it is wed to 
cut out small pieces of the cortex, rather than to fix larger pieces of 
the stem. 
HEMIASCOMYCETES 
Saccharomyces.—Formerly it was considered rather difficult to 
demonstrate the nucleus of the yeast cell. With fresh-growing yeast 
the following method by Wager made the classical demonstration. 
Fix in a saturated aqueous solution of corrosive sublimate for at 
least 12 hours. Wash successively in water, 30 per cent alcohol, 
70 per cent alcohol, and methyl alcohol. Place a few drops of alcohol 
containing the cells on a cover, and when nearly dry add a drop of 
water. After the yeast cells settle, drain off the water and allow 
the cells to dry up completely. Place the cover, or slide, with its 
layer of cells in water for a few seconds, and then stain with a mixture 
of fuchsin and methyl green, or fuchsin and methylin blue. Mount 
in glycerin or in balsam. 
With modern methods, there should be no more difficulty than 
in demonstrating the nucleus in the Cyanophyceae or in the mycelium 
of the Phycornycetes. Use an abundance of vigorously budding 
material, so that you can afford to lose most of it and still have a 
plenty left: Fix in the special chromo-acetic-osmic-acid solution and 
stain in iron-alum haematoxylin. Use the Venetian turpentine 
method, or imbed in paraffin and cut sections about 5 p. 
To obtain the spore stage, put a cake of Fleischmann’s yeast in 
a mixture of equal parts of grape juice and distilled water; add 1 g. 
of peptone and allow to bud freely over night at 30° C.; place the 
material in a plaster-of-Paris cup with a depression, and put the 
cup in a small Stender dish with water coming nearly to the top 
of the cup. In 60 to 70 hours there should be abundant spore 
formation. 
