242 C0L0CASIA feLICHT. 



species considerable difficulty was experienced, but successful 

 cultures were eventually obtained in the following manner. 

 Healthy living conns were placed in contact with fructifying spots 

 on the leaves, the surface of the conn being sliced off at the point of 

 contact. By keeping the surrounding atmosphere saturated, aerial 

 hyphse developed on the leaf and penetrated the corm. The latter 

 was then removed to a moist chamber and a good aerial growth 

 of the fungus, bearing sporangia, developed after a few days. A 

 healthy living corm was next sterilised by washing well in spirit 

 and flaming off the excess of alcohol. It was then divided with a 

 sterile knife and the cut surface placed so as to touch the aerial 

 hyphae of the previously infected corm. After 24 hours the sterilised 

 corm was removed to a sterile moist chamber and gave in subsequent 

 days a copious woolly growth. From this pure cultures were 

 obtained by inoculating tubes of French-bean agar. Other tubes 

 of this medium, as well as of corn meal, were inoculated directly 

 from the first infected corms and purified from the bacteria which 

 contaminated the first tubes by successive subculturing. Ulti- 

 mately pure cultures were grown on the following media : — French- 

 bean agar, corn meal, oat-juice agar, prune- juice agar, and glucose- 

 peptone agar 1 . Cultures on sterilised slabs of Colocasia corm (steril- 

 ised by intermittent steaming in the Koch and placed respectively 

 in potato tubes with distilled water, and on the surface of 



1 Those media were prepared as follows :— 



Frcnch-bcan agar. — 50 grammes dried beans are pounded in a mortar, made up with about 

 300 e.e. distilled water, boiled for half an hour and strained through Hue wire gauze. To this 

 is added 10 grammes agar dissolved in a small quantity of water and the whole is made up to 

 500 e.e. with distilled water. After heating to mix thoroughly it is strained through fine eloth 

 into tubes and autoclaved. The reaction was-f 2 of Fuller's scale. 



Com meal. — Maize meal moistened with distilled water. 



Oat-juke agar. — 50 grammes crushed oats are cooked with about 300 c.c. distilled water 

 for an hour in the Koch and strained through wire gauze. To this is added 10 grammes agar 

 dissolved in water enough to bring the whole to 500 c.c. After heating to mix it is strained 

 into test-tubes and autoclaved. The reaction was + 2 of Fuller's scale. 



Pranc-juicc agar.— 5 prunes boiled in 100 c.c. distilled water for 5 minutes and filtered. 

 To this is added 7*5 grammes agar dissolved in a small quantity of water and, after thorough 

 mixing, the whole made up to 500 e.e. with distilled water, run into tubes and autocla- 

 ved. 



Glucose -peptone agar, — Glucose 10 grammes, meat extract 2 grammes, peptone 5 grammes, 

 sodium chloride 2'5 grammes, agar 7"5 grammes, water 500 c.c. 



