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 ^ 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 

 Melanophis femur-ruhrum 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. AX, 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 growth through the formation of syncytia . The blood corpuscles 

 seemed not to have grown on the other three preparations. Cul- 

 ture tubes were inoculated from these check sUdes 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-ruhrum grasshoppers were injected each with Vio 

 c.c. of a 24 hour bouillon culture of B. poncei. 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. 



