44 Psyche . [June 
microscopically and the organisms were found to be highly motile. 
The cover-slips were kept under observation and at first the bac- 
teria swarmed about everywhere at an exceedingly lively rate. 
The motility seemed to diminish in a few minutes and in 
20 minutes to 4 hour the bacteria had agglutinated in large masses 
and seemed to be dead to all appearances. The four tests were 
identical and I never saw a better reaction with Bacillus typhosus 
and typhoid serum. 
Four depression check slides accompanied the four used in the 
experiment. These were prepared by adding B. poncei to normal 
Melanoplus femur-rubrum blood. The bacteria remained motile 
till the next day. 
The eight slides were prepared under sterile conditions and the 
edges of the coverslips sealed with sterile vasalene, so that I was 
able to keep them for six days. At the end of that time when I 
examined the preparations the agglutination masses presented the 
same appearance in all four experimental slides. The blood corp- 
uscles, however, had divided and formed syncytia. I inoculated 
culture tubes from these four slides, but obtained no growth, 
proving that all the bacteria had been killed. The four check 
slides proved to be interesting in a different way. On them the 
bacteria were not motile, but long chains were visible showing life. 
In some places the bacteria were bunched, but no true agglutina- 
tion masses were found. On check slide 4 the blood showed signs 
of growththrough the formation of syncytia. Theblood corpuscles 
seemed not to have grown on the other three preparations. Cul- 
ture tubes were inoculated from these check slides and pure cul- 
tures of B. poncei were obtained from all. 
I thought it would be interesting to obtain some quantitative 
data in regard to the bactericidal action of immune insect blood. 
Sixteen M. femur-rubrum grasshoppers were injected each with 1/19 
c.c. of a 24 hour bouillon culture of B. poncet. In ten days all 
but three had died, and since no deaths were recorded for four 
days I assumed that the three living animals had acquired immun- 
ity against the bacteria. Small samples of blood removed from 
each showed no bacteria microscopically. Under sterile condi- 
tions the following experiments were performed in small test tubes. 
Adequate checks accompanied the series. 
