28 Annals Entomological Society of America [Vol. XI, 



and an earnest attempt was made to recover B. poncei, but I 

 utterly failed. I inoculated a variety of media from the blood, 

 from various tissues and from the intestines. I plated from 

 these media and tested all suspicious looking colonies on the 

 required media, (media given in my descriptions of organism) 

 in the sugar tubes and performed the nitrate and indol tests as 

 well but without success. About a half-dozen other organisms 

 were found, but B. poncei failed to reveal itself. What killed 

 the grasshoppers? The five deaths represented on Table I were 

 probably due to B. poncei, but the deaths in the three passage 

 infections were due to the careless way in which these experi- 

 ments were carried out. Since this method has been used by 

 practically all workers on this subject, I wish to point out its 

 absolute worthlessness. Grasshopper intestines, as a large 

 number of observations convinced me, are not only often full 

 of gregarines and flagellates, but contain many species 

 of bacteria (intestinal flora). By performing such passage 

 infections as outlined in my tables one simply inoculates the 

 animals with an indefinite quantity of intestinal flora. No 

 wonder the animals succumbed. What then became of B. 

 poncei? This bacterium was either destroyed by the countless 

 other introduced bacteria or was killed by the grasshopper 

 blood cells (phagocytocis) or other immunity principles. If the 

 grasshoppers are to be inoculated in the body cavity why should 

 so many investigators choose the intestines for further passages? 

 Why not perform the passages with the blood? Of course, a 

 sufficient number of the organisms introduced should cling to 

 the outside of the intestines when these are removed, but other 

 organisms within the intestines are likewise introduced. I also 

 failed to obtain pure cultures of B. poncei by resort to blood 

 passages on the animals I used {Melanoplus femur-rubrum and 

 Encoptolophus sordidus) for the reason that the blood seems to 

 act antagonistically towards the bacterium in question and 

 destroys it in most cases. Nevertheless, other organisms are 

 carried along since the toxins or other products introduced 

 cause a disturbance of some sort which in turn causes the gut 

 of the grasshopper to rupture liberating the intestinal flora into 

 the body cavity. 



Tables V, VI and VII represent another series of experiments 

 performed along the same lines as the preceding. The results 

 were exactly similar. I know of no way in which passage 



