142 R. W. GLASER. 



liquefied. In other words it was evident that the organisms 

 secrete a protease. All proteins, however, are not hydrolyzed. 

 For instance, casein does not seem to be effected for after the 

 organisms have been grown in milk for the prescribed time the 

 biuret test did not show the presence of propeptones or peptones. 



It was found that both species of intracellular organisms pro- 

 duce diastase. The organisms were grown in sugar-free bouillon 

 for ten days. After that time the cultures were poured into some 

 pure potato starch paste with 2 per cent, thymol and incubated 

 for 48 hours. Thereupon Fehling's solution was reduced show- 

 ing that sugar had been formed. Check tests accompanied the 

 experimental tests. 



The tests for oxidizing enzymes really do not signify much, 

 for they can be obtained with cultures of almost any bacterium 

 such as B. coll commums or B. prodigiosus. However, both 

 symbionts produce catalase and the Parcoblatta organism demon- 

 strated the presence of peroxidase. 



We may summarize the enzyme activities on the following 

 table and then attempt to correlate some of them with the metab- 

 olism of the insects. 



ENZYMES PRODUCED BY THE INTRACELLULAR ORGANISMS. 



It will be seen from the preceding table that the enzymes com- 

 mon to both species of symbionts are diastase, protease and cata- 

 lase. From the standpoint of Blattid metabolism, I think, dias- 

 tase and protease important. I was disappointed in not being 

 able to demonstrate the existence of lipase, for conditions gen- 

 erally made me feel sure that there was an association between 

 the microorganisms and fat metabolism. 



Both species of insects studied feed primarily on carbohydrates 

 (starches) and proteins, so it was encouraging to be able to 

 demonstrate the two enzymes that effect these two classes of 

 foods. Of course, the insects may feed on fats to some extent, 

 but I think the statement that carbohydrates and proteins consti- 

 tute their principal diet is fairly safe. 



