122 Journal of A gricultural Research V 6 L vni. No. 3 
and for a long time it entirely failed to produce typical blackleg, of the 
stem upon inoculation. This was in accord with the impression one 
would gain as to Van Hall's results relative to pathogenicity on reading 
certain reviews of his paper (15). When Dr. De Zeeuw's translation of 
Van Hall's paper became available, the results of his inoculation experi¬ 
ments appeared in quite a different light. These were quite limited, on 
account of a lack of a sufficient amount of proper material. As is the 
case with any of the pathogenic strains, the inoculation experiments with 
mature stems and tubers gave erratic results or failures. He was able 
in some instances to produce typical blackening and decay when young 
parts of stems were inoculated. 
B. solanisaprus , on the other hand, was originally described in much 
detail, and authentic, virulent cultures are to be obtained by anyone who 
may wish to study it. That used by the writer is as pathogenic to-day 
to potato stems and tubers as when described by Harrison 10 years ago. 
In recommending the dropping of the name “B. melanogenes the 
writer does not wish to be understood as casting any reflections upon the 
work of Pethybridge and Murphy, or upon their conclusions, based upon 
the results obtained by them when compared with published descrip¬ 
tions. The data obtained in the present studies have checked in every 
essential detail with their description of this organism except that the 
writer secured a positive test for indol and was unable to get the forma¬ 
tion of gas in nitrate broth. However, attention has already been called 
to the fact that Pethybridge and Murphy used a broth containing a much 
greater percentage of potassium nitrate than was used by the writer. 
It should be noted that the agreement between B. solanisaprus and B. 
melanogenes resulted from the writer’s obtaining certain results, especially 
with the fermentation of the carbohydrates and the liquefaction of gela¬ 
tin, which were different from those reported by Harrison. Also Harri¬ 
son reports the thermal death point for B. solanisaprus to be 54 0 C., 
while Pethybridge and Murphy say that for B. melanogenes it lies between 
45 0 and 50°. The writer's results showing that the thermal death point 
is approximately 46.5° are then in accord with the latter statement. 
REVISED DESCRIPTION OP BACILLUS ATROSEPTICUS VAN HALL, GROUP NUM¬ 
BER 221.III3522 1 
I. MORPHOLOGY 
Vegetative cells. Medium used was an agar slope at 20° C. 1 to 2 days old. Form, 
short rods, long rods, short chains, long chains. Limits of size in microns (stained 
preparations) 0.4 to 0.8 by 1 to 2 or more. Size of majority 0.5 to 0.6 by 1.5 to 2. 
Ends rounded. 
Endospores, none. 
Flagella, few, not over 6 or 8. Attachment, peritrichiate. Stained by modified 
Pitfield method. 
1 See statement following the list of group numbers on p. 120. 
