1923] 



JENNISON — POTATO BLACKLEG 55 



attention as being extraordinary for the bacillus represented. It 

 would appear that these strains, unlike others of Bacillus atrosep- 

 ticus, inverted cane sugar faster than the hexose by-products 

 were used up. Also, it will be noted that these strains consumed 

 nearly triple the average amount of sucrose used by the other 

 blackleg strains. In this respect these cultures are comparable 

 with B. vulgatus, which is the only other one of the 12 which 

 consumes sucrose so strongly and, in addition, inverts this sac- 

 charide faster than it uses up the invert sugar. It is possible 

 that these 2 cultures (Nos. 195 and 196) were contaminated 

 during the course of these experiments. Neither attracted at- 

 tention because of extraordinary cultural features at the time 

 and so were not plated out. 



Figures are presented in tables xi, xiii, and xiv which 

 indicate a very slight consumption of dextrin by the blackleg 

 strains number 187B.1 and 198. Also, it would appear that 

 minute quantities of starch were used by strain No. 201 (table 

 x), and it would seem that lactose was attacked by B. vulgatus 

 as well as maltose by the yeast species (tables xiii and xiv). 

 The writer is of the opinion, however, that these data in them- 

 selves are slightly misleading. It seems to him more than likely 

 that they appear as the result of small discrepancies which are 

 likely to develop in work of this nature and for reasons which 

 have been stated above. It will be noted that the strain of 

 Bacillus coli investigated did not hydrolyze sucrose nor consume 

 it. Bacillus vulgatus as cultivated in these experiments did not 

 utilize lactose nor did it use more than about a third as much 

 galactose as glucose and fructose. Both these bacteria, it will 

 be noted, attack with considerable avidity all the other carbo- 

 hydrates employed. The yeast species used was unable to at- 

 tack and use carbohydrates presented other than glucose and 

 fructose. These sugars, however, were totally eliminated from 

 the broth by this microorganism. 



The several strains of Bacillus atrosepticus employed in these 

 tests were quite alike in respect to their attack upon and use of 

 the several carbohydrates presented. It appears likely that 15- 

 20 per cent of the amount of the carbohydrates presented would 

 have been sufficient to supply the strains employed, under the 

 conditions of the experiments. The strains of the blackleg bac- 

 illus, furthermore, utilized sucrose, leaving no invert sugar be- 

 hind except in the cases cited above of strains Nos. 195 and 



