STUDIES IN THE PHYSIOLOGY OF THE FUNGI 
IV. Tue Овоутн or Certain Funct ік PraNT Decocrions 
PRELIMINARY ACCOUNT 
В. М. DUGGAR, J. W. SEVERY, anp Н. SCHMITZ 
While undertaking an extensive study of the nutrition of 
Aspergillus niger in the so-called ‘‘synthetic’’ nutrient solu- 
tions it seemed well to determine the growth relations of this 
fungus and others in various plant decoctions, used either 
alone or in conjunction with one or more of the more im- 
portant constituents of the usual synthetic nutrient solution. 
Numerous studies upon the growth relations of certain fungi 
with special reference to the sources of carbon and nitrogen 
have been made by various investigators, likewise consider- 
able work has been done in the direction of determining favor- 
able concentrations of mineral nutrients. Very few data of 
practical importance have come to the writers’ attention bear- 
ing upon the nutrient value of the different plant decoctions 
often employed in culture work. The data here included are 
of preliminary nature, and merely in respect to a few plant 
decoctions, but they are sufficiently definite and suggestive to 
indicate that a complete study of the relations of a consider- 
able number of parasitic and saprophytic fungi to such media 
would throw valuable light upon many problems which con- 
front the physiologist and pathologist in respect to the arti- 
ficial cultivation of such fungi. In the study here reported 
little consideration is given to the relation between vegetation 
and spore formation, but it is our intention to discuss this 
point at length in a later report. 
Realizing the necessity of adopting some standard in the 
preparation of plant decoctions it has been the custom in all 
quantitative work in this laboratory to calculate the amount 
of the raw vegetable product to be used on the basis of dry 
weight. The standard employed! has been 50 grams dry weight 
of the product per liter of water, and this has been found to 
be a satisfactory quantity for most materials. Plant mate- 
1 Duggar, B. М. Fungous diseases of plants. p. 24. 1909. 
ANN. Мо. Вот. GARD., VOL. 4, 1917 (165) 
