at, gs On he a 2 a ee a a ee tS 
’ i 
i 
64 MISSOURI BOTANICAL GARDEN. 
secreted by the fungus is an organic acid whose nature remains 
to be determined. That it is not oxalic acid, as is generally 
supposed, seems to be shown by the numerous experiments 
performed. Smith (49) states that he found as high as two 
per cent of oxalic acid in old culture media, but does not state 
how he demonstrated its presence. The great difficulty in 
this work is to distinguish sharply between the organic acids 
likely to be found in the plant. 
The second part of the work was to determine what en- 
zymes digested the food after the tissue was killed. Attempts 
were also made to ascertain whether the same enzymes were 
secreted on different media. Accordingly, a mineral nutrient 
solution (Pfeffer’s) was used as a stock solution. 
Two strains of the Botrytis were used in the experiments, 
one that had been obtained in pure culture from the lettuce 
in the greenhouse, the other secured in March, from the old 
infected stems of the pepper. Thus one was growing as a 
saprophyte, the other as a parasite. 
A two per cent starch solution with the stock solution was 
used, which formed a paste. Growth was slow for the first 
two days but at the end of two weeks surpassed all of the other 
cultures in the production of sclerotia. In the cultures in- 
oculated with the second strain, more conidia and fewer 
sclerotia were formed, which was the rule in all of the other 
cultures; no other differences were noted. At the end of two 
weeks the medium gave no reaction with iodine. Fehling’s 
solution showed a strong reduction. With Barfoed’s reagent 
a positive reaction was obtained, and with phenylhydranzine 
a brownish osazone was precipitated. The crystals, when 
microscopically examined, appeared to be glucosazone, which 
was further substantiated by their insolubility. The results 
show that a large amount of diastase is secreted by the fungus. 
Smith (49) reports that he was unable to obtain any growth 
whatever on starch, possibly due to some toxic substance in 
the commercial corn-starch used by him. 
As a check on the above work, the action of the extract on 
a starch solution was observed. Using equal volumes of starch 
