Dec 8,1933 
Hornworm Septicemia 
483 
disease a bacillus to which he gave the name Coccobacillus acridiorum . 
Glaser ( 2) made a study of a number of cultures which had been isolated 
and identified as Bacillus 7 ( Coccobacillus) acridiorum and found a con¬ 
siderable variation among them. Of those he compared, two were re¬ 
ceived from d’Herelle designated as “souche sidi” and “souche cham,” 
respectively. Some differences were noted in these two also. The two 
from d’Herelle were obtained by the writer from Dr. Glaser in order that 
B. sphingidis might be compared with them. It was soon demonstrated 
that B. acridiorum and B. sphingidis were related species and should be 
placed in the same group of organisms. 
The serum of a rabbit 8 * * immunized with Bacillus sphingidis and show¬ 
ing an agglutinin titer of 1:4,000 for the culture of B. sphingidis , used 
in the immunization, did not agglutinate either the 11 souche sidi” or 
“souche cham” strain of B. acridiorum . Homworms, silkworms, and 
the larvae of the catalpa moth were killed in slightly less time from punc¬ 
ture inoculation with B. sphingidis than with B. acridiorum . 
PREDISPOSING CAUSES 
Tittle is known concerning the predisposing causes of hornworm sep¬ 
ticemia but it seems quite certain that there are important contributing 
factors besides the exciting agent. From the foregoing pages it is seen 
that a septicemia and the death of the worm follow readily the intro¬ 
duction of Bacillus sphingidis into the blood by puncture inoculations. 
If in nature the organism reaches the blood through the chitin-covered 
body wall, such entrance, it would seem, must be accompanied by an 
abrasion of the wall, the introduction of the germ, if it occurs at all, 
being more likely at the time of the trauma. 
If the portal of entry of Bacillus sphingidis in the production of the 
septicemia is by way of the alimentary tract, as seems quite probable, 
evidently there are here also some very effective protective forces of the 
host which must be overcome before the bacillus is able to gain entrance 
to the blood. What these are is another interesting problem only par¬ 
tially solved. 
The age of the larva seems to be one of the predisposing causes, infec¬ 
tion being more likely to occur during the fifth instar. Temperature 
may be another, warm weather seeming to predispose the larva to the 
septicemia. Differences in susceptibility before, at, or following the 
molting period, if indeed there are any such, have not been determined. 
7 Inasmuch as Coccobacillus as a generic name does not occur in systems of classification ordinarily fol¬ 
lowed by American writers. Bacillus, more generally employed, is used in the present paper. 
f The rabbit was injected intravenously with z cc. of a normal salt suspension of Bacillus sphingidis 
made from a 34-hour agar culture, containing about 100 million organisms. Similar injections were re¬ 
peated weekly until five of them had been made, using each successive time a like suspension but of 
increased density. The rabbit was bled one week following the last injection. 
A two-day bouillon culture was found to be a very suitable one for making the agglutination test. This 
was diluted to the desired density with a one-half of 1 per cent solution of carbolic acid in normal salt. 
The macroscopic method was followed using room temperature. The clumping was evident within a 
short time, but the final reading was usually made after the tubes had stood overnight. 
The agglutination test with this species is very satisfactory, the positive tubes clearing completely while 
the control suspension remains uniformly clouded with no tendency to clump and with only a slight ten¬ 
dency to settle. There is no agglutination with normal rabbit serum. Agar and old bouillon cultures 
may be used but were found to be less desirable than the two-day bouillon ones. The test was satisfactory 
also when a one-half of 1 to 1 per cent carbolized suspension was used, but when a 2 per cent one was 
employed it was apparently somewhat impaired. Bouillon cultures when heated to 65° C. for 10 minutes 
proved to be as useful in the test as the carbolized unheated ones. When heated to 80 C., however, their 
agglutinability was somewhat impaired and when boiled for 10 minutes it was destroyed. 
The immune serum, after being drawn, was diluted 1:3 with normal salt solution carbolized to one-half 
of z per cent, sealed in glass ampules, and kept at room temperature shielded from light. Tested after 
more than two and one-half years the agglutinating power of the serum was practically unimpaired, but 
when tested still a year later this property was found to be virtually lost. 
