259 



The most stnking fact in thèse observations is the small amount 

 of diastase formed on saccharose. As far as I know, no investigators 

 before me found such large différences of diastase production on 

 starch, glucose and saccharose. Katz and Kylin always speak of 

 "reichliche Mengen", but this may be so, because they always 

 mixed their saccharose with 0.25% starch. Most other investiga- 

 tors give equally vague indications, and w^e may drav^ the con- 

 clusion that they never found much less diastase production on 

 saccharose than on other sugars. It is possible that in my case the 

 large dry weight of the mycélium may hâve influenced the results. 

 We can safely imagine this to be the case for the séries on 

 cane sugar + Fe" + Zn.. Hère the weight amounted to 1426 

 and 1417 mgrs. and perhaps we may add to this a possible dis- 

 advantageous influence of the iron and zinc. In the S S and G S 

 séries it is much less probable that we should consider the influ- 

 ence of the dry weight (989 and 1059 mgrs.). In the first case it 

 only differs very slightly from that of the séries G G (944 mgrs.) 

 where there was a considérable development of diastase. In any 

 case it is conceivable that this small increase in dry weight just may 

 be able to turn the scale. 



If ail this is true, we might expect that Aspergillus niger should 

 produce large quantities of diastase when cultivated on lower con- 

 centrations of cane sugar, e. g. 1%. I tried to find out if this really 

 was the case. For this purpose I made six cultures on 1% sac- 

 charose (with conidia from a 4% glucose culture). Two of thèse 

 I examined on the 7 , 14 and 2P* days. The results may be 

 seen in the foUowing table: 



•* This resuit is the average of the observations on two cultures. 



