22 A. L. PlERSTORFF 



invert sugar than did the check tubes. It appears that the bacteria 

 used this sugar in growth processes. 



From these tests it is apparent that B. amylovorus can split sucrose 

 and utilize the reducing sugars for growth. 



Maltase 



A solution similar to that used for invertase was employed in testing 

 for maltase, maltose being substituted for sucrose. In each of eight 

 test tubes 10 cubic centimeters of this solution w T as placed, and this 

 was incubated for ten days at 23° C. after inoculating four of the tubes. 

 At the end of ten days the solution in two uninoculated tubes was 

 tested, without inversion, with Fehling's solution, and it yielded a mean 

 of 198.0 milligrams of maltose; two culture tubes similarly treated 

 yielded 182.4 milligrams of maltose. The maltose in the four remain- 

 ing tubes was inverted by boiling for two hours with hydrochloric acid. 

 The two check tubes gave a mean of 205.5 milligrams of glucose; the 

 two culture tubes gave a mean of 180.2 milligrams of glucose. 



Since glucose has approximately 2.32 times the reducing power of 

 maltose on Fehling's solution, it was thought that perhaps the culture 

 tubes would yield more cuprous oxide than would the check tubes, 

 especially if Bacillus amylovorus excretes a considerable amount of 

 maltase. Such was not the case. It is only after inverting the maltose 

 to glucose and determining the total sugar in the solution, that con- 

 clusive evidence of maltase formation is found. Apparently the bacteria 

 utilize glucose about as rapidly as it is formed. 



The bacteria grew luxuriantly, and this fact would lead to the belief 

 that maltose was utilized. It was found, however, that a small amount 

 of bacterial growth would take place in Uschinsky's solution without 

 sugar, glycerin, or CaCl 2 . Apparently the bacteria are able to split 

 sodium asparaginate sufficiently to enable them to utilize carbon from 

 that source. 



Amylase 



Soluble starch was substituted for gylcerin in Uschinsky's solution 

 in testing for amylase. Ten tubes containing 10 cubic centimeters each 

 were prepared, and half of the lot were inoculated. The prepared 

 solution readily reduced Fehling's solution. Aften ten days of incuba- 

 tion the starch was converted to hexoses which reduced Fehling's solu- 

 tion. The results were so variable that no significance could be attached 

 to them. It remains to be demonstrated whether or not Bacillus amy- 

 lovorus can utilize starch through the secretion of amylase. 



When Burrill (1882) described the causal organism of fire blight, he 

 named it Micrococcus amylovorus, meaning "starch-loving." Most 

 workers since Burrill 's time have held that B. amylovorus does not 



