20 fe' l*i- 35 H« ■>■/. i.'i In "ft" «^ 'I- a fi^J i?f ^ 



tion of Trof, Mi)';ilH' and affirmed tliat the flax-wilt iliscase is caused by 

 Fiisariinii, and to contnil the disease a long interval of rotation of crops is 

 absolutil)' necessar)-. IVfore this, in America, Prof O. Luggar carried out 

 a \aliiable investigation of this disease, but lie did not succeed in finding out 

 its causal organism. Li 1901, I'rof II L 15olley discovered quite inde- 

 pendent!)' withe lilt hnowing tlu: lesult of the researches by Dr. Miyabe and 

 Dr. ] liratsuka, tlu- causal fungus of the flax-wilt disease, and named it 

 Fiisariiivi liiii. 



In recent years the disease of plants caused b)- the sjjecies of Fusarium 

 ha\'e assumed great impcM'tance from an economic as well as from a scientific 

 standjioint A large amount of work has been done on the taxonomy and 

 proplu'lax)- of these fungi and on the diseases the\' prothice, but tliere hav^e 

 bii'u com]iarati\eh- few studies in regard to the relations of physiological 

 characters of these fungi. ^\bout the physiology of F7isari7im lint W. H. 

 'I'isdale has reported on a temperature study. 



I ha\e carrieil out an imestigation on some physiological characters of 

 this fungs for tiK- further iii\-estigatioii of the wilt disease of flax. 



The writer wishes to express here his sincere thanks to Prof Dr. K. 

 RTi}abe for his kiiiil direction, and he is also indebted to Prof Dr. S. Ito 

 and Dr. T. Hemmi for the main- valuable suggestions. 



I. General Cultures 



1. Apricot-juice agar 



Steep 200 grams of seedless dried apricot in 500 cc. of distilled water 

 for 24 hours and filter through filter paper. Melt 30 grams of agar in 500 

 cc. of distilled water in boiling water bath and precipitate the impurities 

 with white of egg and strain through cotton. Mix these two solutions. Fill 

 10 cc. of the fluid in to each test tube. Sterilize them in Koch's steam 

 sterilizer for 20 minutes twice with one day's interval. Then incline them 

 and let them set as agar slants. 



