TOCHIXAI : STUDIKS ON THK PHVSIOI.OGY OF Flisarluill Ulli. 35 



FrocUiction of the chlamj-dospores is generally poor. In the No. 9 cultures 

 I: could observe the chlanij-dosporc-formation microscopically, notwithstanding 

 the liyphal growth is scarcely detected macroscopically. 



Production of conidia is vigorous in the cultures of low percentages of 

 citric acid. 



From the results of these experiments I have drawn the following 

 conclusions : — 



1. Small quantities of citric acid existing in the culture media are 

 favorable for the fungus. Citric acid seems, however, not to serve much for 

 nutrition, it may only do so for a carbon source, but as there is cane sugar 

 present in the culture medium, there may not be any necessity for the fungus 

 to utilize the carbon of another carbon-source so difficultly assimilable as 

 citric acid. 



2. Citric acid retards the formation of the conidia. In the aciil-frcc 

 medium the fungus produces conidia abundantly. With the increase of the 

 acid percentage conidial formation become gradually less. 



3. In the preceding citric acid cultures with the synthetic solution, the 

 growth of the mycelium was checked even by i-SX concentration of citric 

 acid, but in the case of the potato agar medium even by the 3^ concentration 

 of acid the growth of the fungus was not checked. Acidity of the standard 

 medium may have caused such a difference. 



4. Chlamydospore-formation was induced by citric acid. In the acid- 

 free cultures the chlamydospore-formation was observed rarely after 10 days 

 from inoculation. In the cultures of higher acid percentage it was somewhat 

 vigorous considering the poor growth of the mycelium. When the cultures 

 became old, chlamydospores were produced more and more even in tin- 

 cultures which contain citric, acid in low percentage. 



IV. Efifects of Temperature on the Fungus 



Investigation of the relation between temperature and growth of the 

 fungus or infection is very interesting biologically, and at the same time 

 very important economically. 



There are many reports of temperature studies on different kinds of fungi. 



