222 



tion of glucose, containing the usual inorganic salts. Every day, 

 later on every second or third day he tested whether there was any 

 diastase présent in the mycélium and in the culture liquid, and if 

 diastase was found, he determmed the concentration of the enzyme. 

 In this way he was able to détermine the influence of the âge of the 

 organism on the sécrétion of the enzyme, and to find at what point 

 this sécrétion is at a maximum. 



If the same is done with culture solutions of différent composi- 

 tion toWent's, we may be able to coUect matenal from which some 

 valuable conclusions may be drawn. This was the object of the 

 following research. 



I hâve only quoted the literature in broad outlines; under the 

 varions subdivisions of this subject I shall always refer to the articles 

 concerned with that part of it. 



II. METHOD OF INVESTIGATION .AND SOURCES 

 OF ERROR. 



A. Method of investigation. 

 The method of doing this type of research has been fuUy des- 

 cribed by Went. As my method differed only very sligthly from 

 his, a brief description should suffice. 



The following salts and concentrations were used in ail the cul- 

 ture solutions 



NH4NO3 0.5 % 

 K,HP04 0.1 % 



MgS04 0.05% 



Thèse remained unaltered ; as organic foodmatenals carbohydrates 

 chiefly were added to this solution. Their concentration and com- 

 position will be given as each experiment is discussed. 75 ce. of 

 this solution were poured into a flask, and after being sterilised, 

 they were ail inoculated with the fungus at the same time. 40 à 50 

 flasks formed one séries. The solutions were inoculated in the 

 following way a quantity of conidia was brought into a test tube 



