532 
ADRIAN J. PIETERS 
protoplasm, as well as the weight of the product, such effects should 
become evident when m^^celia, grown in different culture media, are 
transferred to solutions of identical composition and concentration. 
The new and uniform environment acting upon the protoplasmic 
product of varying environments may be expected to bring out 
differences if any exist. Data will be presented in this paper to show 
that, in some cases at least, such an effect, not to be measured in terms 
of dry weight produced, has resulted from the use of special culture 
media and that there is no direct and necessary relation between 
weight of mycelium and the production of oogonia. 
It was realized at the outset that there were two aspects of the 
problem — the quantitative and the qualitative. Either a nutritive 
substance of one kind might affect the organism because of its greater 
abundance, or substances of various kinds might affect especially the 
reproductive capacity or the vegetative growth. 
Solutions were therefore prepared with these two aspects in view, 
different concentrations of peptone being used on the one hand and 
various carbohydrates and salts on the other. The number of oogonia 
produced on the mycelia after transfer, together with the weight of 
mycelium in the duplicate lots left in the nutrient solutions, make 
up the evidence on which the conclusions reached are based; this 
evidence can best be presented in a series of tables and as tables are 
rather uninteresting reading, the writer has pointed out briefly after 
each table the conclusions that seem warranted by the evidence, 
leaving a general discussion of these conclusions to be given at the 
end of the paper. The chief contributions which it is believed are 
made by the present work to our knowledge of the physiology of these 
forms are the recognition of a minimum concentration of food necessary 
for a full development of the plant, and the fact that above this mini- 
mum an increased concentration during vegetative growth does not 
necessarily increase the reproductive capacity of the fungus. It 
developed further, as will be shown in the following pages, that certain 
carbohydrates are readily used while others can not be utilized, and 
that of those that are used some are of more value to the plant for the 
formation of reproductive organs than others. 
Material 
The material used for this study consisted of four species of Sapro- 
legniaceae, selected from among a larger number isolated and studied. 
