INTESTINAL PROTOZOA OF TERMITES. 



mention here that, because of the success of the incubation 

 method, many of the other attempts to free termites of their 

 intestinal protozoa were, perhaps, not given a fair trial. If 

 different dilutions of some of the chemicals had been used, the 

 results, possibly, would have been more promising. Had X-ray 

 and ultra-violet light been used more extensively, excellent re- 

 sults might have been obtained. 



It was found that all not one was left alive of the protozoa 

 could be removed from the intestine of ReticuUtermes flavipes by 

 incubating them for 24 hours at 36 C. This was a much more 

 rapid method than the feeding of salts, as described above, where 

 several days are required to remove the protozoa from all the 

 individuals in a colony and, besides, the termites after incubation 

 seemed to be perfectly normal in every way. All other attempts 

 to remove the protozoa were now abandoned in favor of the in- 

 cubation method, which may be briefly described as follows: 

 Sometimes slumps and large pieces of wood, containing thousands 

 of termites, were brought to the laboratory without molesting 

 or disturbing the colony. The stumps and large pieces of wood 

 were placed in glass jars and incubated for 24 hours at 36 C. 

 At the end of the incubation period the jars were taken from the 

 incubators and, after many termites from each jar had been 

 carefully examined to be certain that the protozoa had all been 

 killed, were left at .room temperature, which was usually about 

 2oC. Sometimes the stumps and logs were split before they 

 were brought to the laboratory and the termites were taken from 

 them and placed, with a good quantity of wood, in glass jars with 

 metal tops. These jars were placed in the incubator as soon as 

 they reached the laboratory. In other experiments, where ter- 

 mites were counted, small shell vials with cork stoppers were 

 used, and from 10-100 termites were placed in each vial, and 

 incubated in the same way that those in the large jars were. 

 Several vials of termites without wood, and several with pure 

 rellulose ' (Whatman's filter paper) only, were incubated. Other 

 experiments in incubation were carried out with results as shown 

 in Table I. One very significant fact brought out by these ex- 



1 This paper was made by \V. & R. Balston, Ltd.. and contains .0004 grams of 

 ;i-li per circle of 55 mm. diameter. When "pure cellulose" occurs in this paper it 

 iners to this grade of the genuine Whatman filter paper. 



