2o6 



Journal of Agricultural Research voi. xviii, no. 4 



It was considered advisable to precipitate the gum, filter, and again 

 polarize the solutions after two days' incubation. These values are 

 shown in the last columns of Table X. 



The same general relationships as noted in the solutions containing 

 gum were again established. The fact that some evaporation occurred 

 and that these polarizations were made with a loo-mm. tube accounts 

 for the slightly higher values obtained. 



After 2>2 days' incubation the solutions were again polarized and re- 

 ducing sugars determined, with the results recorded in Table XL 



Table XI. — Atialyses of 10 and 20 per cent sugar solutions inoculated with spores oj 



A spergillus sydowi 



10 PER CENT SUGAR SOLUTION 



20 PER CENT SUGAR SOLUTION 



10 cc. sterile water heated to 63° C . 

 10 cc. sterile water heated to 100° C 



10 cc. spores heated to 100° C 



5CC. sporesheated to 63° C 



10 cc. spores heatedt 063° C 



20 CC. spores heated to 63° C 



0.08 



•37 

 I. 00 



1-45 



It is at once apparent that there is a striking decrease in sucrose 

 accompanied by an increase in reducing sugars wath an increase in the 

 number of spores used for inoculation, and that as with the spores 

 of Aspergillus niger the invertase activity is manifest to a greater degree 

 in the 20 per cent than in the 10 per cent sugar solutions. 



In order to identify the invertase and gum-forming enzyni with the 

 spores of Aspergillus iydowt alone, each solution was examined micro- 

 scopically and plated out in the usual manner on Kopeloff 's agar.^ No 

 contaminating bacteria or other microorganisms were to be found. 



Having established that the spores of some molds contain invertase 

 and a gum-forming enzym, it is essential to define the limits of concen- 

 tration under which these enzyms may operate. Consequently, a 70 



1 Kopeloff, Nicholas, and Kopeloff, Lillian, op. cit. 



