Dec. 8 , 1923 
Hornworm Septicemia 
479 
infection therefrom. By the feeding method the leaves given the larva? 
as food are first dipped into an aqueous suspension of the culture or of 
the tissues of worms sick or recently dead of the disease. 
From a study of the blood of sick worms and of those dead of the 
disease a bacillus was found in very large numbers and in pure or almost 
pure cultures. When healthy worms are inoculated with a pure culture 
of this bacillus by the puncture method the mortality is 100 per cent. 
The sick ones show symptoms and the dead ones post-mortem changes 
that are similar to those observed in worms which become infected in 
nature. In microtome sections of sick worms one sees further proof 
that the condition is a septicemia, the bacilli being found throughout 
the blood spaces. They appear particularly numerous 4 * between the 
folds of the stomach wall. 
The name Bacillus sphingidis 6 is here used for the bacterium which 
has been encountered in this disease. 
Bacillus sphingidis n. sp. 
This species grows readily in all of the common and differential media ordinarily 
employed. Good growth is obtained in media whose reaction varies from +1.5 to 
Fig. i. —Bacillus sphingidis. 
Fig. 2.—The flagella of Bacillus sphingidis. 
—2 per cent, and occurs also 1 per cent or more beyond these limits, but it is then 
less rapid and less extensive. For incubation a wide range of temperature is suitable. 
That of the room is very satisfactory and was used for most of the work. 
Morphology. —The organisms of a 24-hour plain agar culture are small, short rods 
with rounded ends, many forms being coccoid and ovoid; the coccuslike ones measure 
about 0.6 micron in diameter and the ovoid ones about 0.5 by 0.75 micron. (Fig. 1.) 
The forms which are distinctly rod-shaped are from 0.8 to 1.5 microns in length and 
from 0.5 to 0.7 micron in wiath. In bouillon cultures the rod forms predominate 
and average larger than those from agar. Long rods and even filaments not infre¬ 
quently occur in older bouillon cultures. No spores are produced. The small forms 
on agar have most frequently one flagellum each, although sometimes two and occa¬ 
sionally more (fig. 2) are possessed by a single bacterium. They are usually attached 
near an end of the rod. 
Motility. —The bacillus is actively motile. The movements, aside from being 
progressive, are usually decidedly whirling. 
Staining properties. — It stains easily and uniformly with the usual aniline dyes 
and is gram-negative. 
4 That some of the bacilli escape from the blood to the alimentary canal is shown by their presence in 
large numbers, in worms inoculated by puncture, in the thin alvine discharges that occur during the latter 
part erf the course of the disease, but the mode erf exit from the blood has not been observed. The larger 
number in the blood spaces between the folds of the stomach wall may be partly, or indeed wholly, due 
to the technique used in the preparation of the slides. 
* This name was suggested by Dr. L. O. Howard. 
