492 



shows a considerable iiicrease. These experiineiils (lid iiol last long 

 enough to show what the further course would be, and for this 

 very reasoji the last series of tlasks was started, in order to trace 

 for a longer time the behaviour of Aspergillus niyer in this respect. 

 It was found that here also after about one month the rise of tlie 

 enzyme-conteni occurred; thereupon there followed again a decrease 

 and then again a rise, whilst after about three months the decrease 

 became permanent, so that finally practicall} no diastase remained. 

 The oscillations of this curve are explicable by considering that the 

 great rise in the first 3 — 4 days coincides with a vigorous develop- 

 ment of the young mycelium. The same takes place again later 

 when the fungus has formed new conidia and these, having been 

 shed into the culture-fluid, germinate there; each time that this 

 happens a sudden increase in the quantity of the diastase will be 

 observable. It is self-evident that it cannot always be predicted 

 at what time in the course of the culture this will occur, but we 

 may safely argue that the culture-fluid gradually will become less 

 and less suited for (he germinalion of the conidia, and thai therefore 

 this phenomenon will- gradually stop altogether. If this explanation is 

 correct it would therefore be possible to make the fortnation of diastase 

 in Aspergillus niger go on for a much greater length of time by 

 renewing the nutrient solution. 



The phenomena which have just been described are thus of a 

 secondary character and all study of the formation of enzyme in 

 Aspergillus niger must be limited to the first stages of development. 

 One cannot indeed say whether the course of the formation of enzyme 

 would be the same with different nutrition, but this may however 

 be expected. It is therefore not only impermissible to draw conclusions 

 from the quantities of enzyme which occur in cultures which are 

 e.g. some weeks old, but "one must try to follow accurately the 

 course of the enzyme-formation during the first days of development 

 of the fungus in the case of each kind of nutrition; then only can 

 conclusions be drawn respecting the influence of a given nutrition 

 on the enzyme-formation of Aspergillus niger. 



It is evident that these conclusions oidy concern the formation 

 of 'diastase in Aspergillus niger; but they will nevertheless oblige 

 one to be careful about conclusions as to other enzymes and other 

 fungi; in further investigations the possibility must be borne in 

 mind of similar results occurring. 



Summing up, it is found that in Aspergillus niger during the first 

 days after germination a great quantity of diastase is formed in the 



