480 



only endeavoured to solve the problem in one definite case, liow 

 the formation of diastase takes place. P'or the cnltiire-fhiid a solution 

 was always used containing 5 7, glucose, 0.5 '/„ NH,NO„ 0.1 •/„ 

 K,HPO, and 0.05 % MgSO,. This solution was sterilised by heating 

 it on three successive days for hal f-au- hour to 100° C. 



The inoculation was carried out by means of a platinum loop 

 with fluid containing the conidia of Aspergillus. It is known that 

 the latter remain floating on the surface of the fluid and that one 

 cannot keep them submei-ged. One can lake care to get a fairly 

 uniform distribution on the surface of the fluid and then always 

 inoculate the same amount with a loop. Thus one does not indeed 

 obtain a complete uniformity of the number of conidia in the 

 different cidture flasks, but the differences are so small as to exercise 

 no influence on the final result, at most a slight difference in 

 development is observable in the tii-st two days. It should be possible 

 to ensure a greater uniformity of inoculation-material, but this 

 would be fraught with so many difficulties that it is not worth 

 while in view of the very small advantage it would yield. It needs 

 no demonstration that the sowing of a single conidium is here 

 wholly impermissible, because then one woidd have to reckon with 

 great individual diffei-ences. These differences can only be compen- 

 sated for by inocidation with a large numbei' af conidia. 



The fungi were grown in glass (Erlenmeyer) flasks and for com- 

 parative experiments the same quantity of culture-fluid was always 

 placed in similar flasks. The latter were kept in a room at a 

 constant temperature of 24° C. with variations of 0.5°. 



The cultures were in darkness; artificial light only was used for 

 inoculation and observation. 



At flrst daily and later after two, three and more days determi- 

 nations were made of the amount of enzyme present in the culture- 

 fluid and in the fungus-mass of one of the flasks, but generally 

 this determination was made for 2 oi- 3 flasks. Then at the same 

 time the fungus-mass formed in one of the flasks was collected on 

 a tared filter and weighed after it had been dried, so that an idea 

 was obtained of the quantity of dry material which had been formed. 

 The other fungus-mass was ground fine in a mortar with the help 

 of a little kieselguhr, and afterwards extracted for one hour with 

 the culture-fluid and subsequently this fluid was filtered off and 

 examined with regard to enzyme: now if we know the quantity of enzyme 

 present in the culture-fluid, which had therefore diffused outwards, 

 then we have only to subtract this from the quantity found in order 

 to ascertain how much enzj nie was present in the mycelium. 



