225 



case the time taken is 54 min., then the quantity of enzyme will be 



150 



— -X 100= 277.8. 

 d4 



Besides the dry weight of the mycehum and the amount of 

 diastase, I also tested the degree of acidity of the culture solution 

 and of the mycélium extract regularly, and I sometimes also tested 

 how much sugar was left in the culture solution. 



What remained of the différent solutions was carefully stored. 

 Thèse were used on the following days to see how long the liquid 

 retained its fermentative action. I shall return to thèse in détail 

 later on. 



For the sake of completeness I may mention, that the influence 

 of alien organisms is excluded by adding a few drops of toluol to 

 the liquids. 



The mail) objection to this method is in my opinion, that by 

 testing with lodine, the time of hydrolysis can not be determined 

 with a sufficient degree of accuracy. Of course tcsting it by means 

 of rotation or by power of réduction would be much more accurate, 

 but very difficult because of the low concentration of starch used 

 for the expenment. Besides, for m y subject, very great accuracy 

 has no practical value, because I only use the results to compare 

 them with others in a long table, the sumtotal of the columns of 

 which give me an indication of the course, followed by the enzym^e 

 sécrétion. .As we shall see later, 1 hâve been rather successful in 

 obtaining a clear idea of this, even though my conclusions are based 

 on the observations of more than one culture. For unluckily we 

 are forced to deal with a large number of cultures m which individ- 

 ual différences are unavoidable. I hâve reason therefor to believe 

 that this lack of accuracy can not be regarded as such a serious draw- 

 back, that it would prevent us from knowing exactly, how the sé- 

 crétion of the enzyme goes on during the lifetime of the fungus. 



A very great advantage of this method is, that it takes so little 

 time. It wes only because of this, that I hâve been able to investi- 

 gate about a thousand différent cultures. I need not point out that 



