IO 



half grown, in the latter the size of a horse-chestnut. Ten inocula- 

 tions of Whitehead were not successful where the fruit was less than 

 one centimeter in diameter. 



CULTURAL RELATIONS OF THE FUSARIUM. 



Following as far as practical the method of Prof. R. E. Smith 6 in 

 his work on Botrytis, cultures of the Fusarium were made on media 

 of such vegetable substances as it was likely to meet with during 

 its growth on the fruit. The mineral stock solution used was as 

 follows : 



Potassium nitrate, 5.0 grams 



Magnesium sulphate, 2.5 grams 



Potassium phosphate, 2.5 grams 



Calcium chloride, 1.0 gram 



Water, 1000 c.c. 



More nitrogen was supplied in the form of peptone. Each of the 

 following substances was added separately to 200 c.c. of the stock 

 solution in the proportion indicated : 



Malic acid, .5$, 3$, iofc ; oxalic acid, .5$ ; tartaric acid, 2$ ; tannic 

 acid, 2% ; cellulose, small quantity ; corn starch, 2^ ; glucose, 2$ ; 

 cane sugar, 2^. As usual, duplicate flasks were prepared in each 

 case which were left uninoculated for comparison. 



Malic acid. This was the first acid tried, and as some species of 

 Fusarium are known to grow best on an acid medium, a variety of 

 strengths were tested. The acid of the tomato has been stated to 

 be approximately .5$ malic. Contrary to expectation, there was no 

 growth in the two stronger solutions, very slight and long deferred 

 growth in the .5^. 



Oxalic acid. Growth fairly good. Slow in starting. 



Tartaric add. No growth for a week or more, then very slight 

 growth. 



Tannic acid. A little slow in starting, but finally a vigorous 

 growth. After the surface was covered, a darkening of the solution 

 took place from the top downward, turning from a light yellow to a 

 deep wine color. 



Glucose. Growth vigorous from the start. 



