242 PovaH: A CRITICAL STUDY OF 
Dr. C. H. Kauffman, whose constant interest and helpful criticism 
are hereby gratefully acknowledged by the writer. 
II. HISTORICAL 
I. CULTURE METHODS 
In De Bary’s Morphologie und Physiologie der Pilze, Flechten 
und Myxomyceten (1866) the application of cultural methods 
to Mucor is mentioned for the first time, in the following words: 
“Sie [Mucor Mucedo] wachst spontan und in den Culturen auf 
faulenden Friichten, Speisen, Zuckerlésungen und besonders iippig 
auf Mist.”’ To Brefeld (1872), however, belongs the honor of having 
been the first to realize the necessity of employing the single spore 
culture method. On page 25 of the first Heft of his Botanische 
Untersuchungen iiber Schimmelpilze, we read the following: ‘Der 
Weg der Cultur einer einzelnen Spore unter liickenloser Verfolgung 
ihrer einzelnen Entwicklungsmomente, unter Vermeidung der 
vielen und zahlreichen Fehlerquellen, wie sie durch Invasion 
fremder Pilzsporen entstehen, kann allein die Basis fiir die Kennt- 
niss und Klassification dieser Schimmelpilze abgeben.”’ His 
method was very simple. He placed on a slide a single spore in 
a drop of freshly prepared horse dung decoction. The slides 
were observed directly under the microscope and when not in 
use were kept on a zinc plate covered with a bell jar standing in 
water to keep the air moist. He undertook a study of Mucor 
Mucedo (De Bary says “at my instigation’’) in order to learn 
whether De Bary was correct in his “apparently irregular pleo- 
morphy” conception of the ‘‘collective so-called Mucor Mucedo.” 
As a result he found that De Bary, owing to his crude culture 
method, had been dealing with an impure culture, having intro- 
duced Chaetocladium into the cycle of Mucor Mucedo. 
G. Klebs (1898) does not go into detail with regard to his 
culture methods, nor does he mention a single spore culture. He 
used, for media, those substances which had proved the most 
favorable for the mold he was studying (Sporodinia grandis Link). 
These he found to be bread soaked with plum juice, slices of carrot 
and plum juice agar. | 
Oudemans and Koning (1902), making a study of the myco- 
logical flora of the soil of the Netherlands, give their technique in 
