170 The Philippine Journal of Science 1915 
iments, broth was inoculated from young cultures, and in some 
cases directly from the body cavity of infected insects. In one 
of our field-corral experiments a considerable number of insects 
died after inoculation with one of the exalted strains. These 
insects were collected, crushed in broth, and the broth, after 
two or three hours’ growth, was sprayed in the open field. 
Our one partially positive field experiment followed a spraying 
of this material. We gave our personal attention to the 
spraying and examination of the swarms. 
Since the insects usually did not begin to feed freely until the 
day was well advanced, it was thought that our negative results 
might be due to the fact that the insects did not ingest a sufficient 
quantity of culture before it had been killed or attenuated by 
the heat or dryness. So another method of feeding was employed 
in some later experiments. Fresh broth cultures were mixed 
with rice polishings (tiqui-tiqui) and a small amount of sirup im- 
mediately before being set out for the insects in the field. The 
insects fed on this mixture greedily, collecting on it immediately 
after it was exposed. Two such experiments gave results as 
clearly negative as the ordinary spraying. Intermittent spray- 
ing practiced on the same swarm during the course of a morning 
likewise gave negative results. 
The fields were visited on the day following spraying and 
usually on several subsequent days, and careful search was made 
for dead or infected insects. As stated before, only one experi- 
ment gave partially positive results. This experiment was con- 
ducted in an open paddy field during a relatively wet period. 
The material sprayed was broth in which were crushed a large 
number of insects found dead in a corral experiment. A consid- 
erable number of insects, amounting perhaps to several liters, 
were found dead in the field the following day; although the dead 
were but a small percentage of the total swarm, and apparently 
there was no marked diminution of the swarm. There was ab- 
solutely no indication of a natural spread of the infection in this 
Swarm, and cultures from dead insects found in the field and 
emulsions of the body contents of these insects failed to give 
positive results in subsequent sprayings. In no case was there 
any indication of the prevalence of diarrhea among insects in 
the field. 
We do not believe that our failure to obtain field results of 
practical value was due to any error in technique or any lack of 
thoroughness in the test. Two conditions may have contributed 
to make our results less successful than those reported from 
