210 L. R. CLI-.X I I \\D. 



Now, since the incubated and defaunated termites remain 

 alive and active indefinitely (See Table III.) when fed humus 

 which is wood (chiefly cellulose) digested or decomposed by 

 bacteria, fungi, actinomycetes and digested cellulose, but die 

 when fed wood or when fed cellulose, it seems very probable that 

 death is due to an inability to digest wood. Futhermore, it has 

 been shown that no sugars can be gotten from wood except by 

 first extracting the cellulose, which probably means that the 

 sugars exist in combination with the cellulose. Then, we may 

 reasonably conclude that the inability on the part of the defaun- 

 ated termites to digest wood is due, perhaps, to the disappear- 

 ance of cellulase, brought about, in some way, by the incubation 

 and removal of the protozoa. 



If cellulase is no longer present in termites after incubation 

 and it does not seem to be what is responsible for its disappear- 

 ance? In order to answer this question the two factors involved 

 in bringing about the disapparance of cellulase, incubation and 

 the removal of the protozoa, must be separated. Reinfection of 

 the incubated and defaunated termites with protozoa seemed to 

 be the principal key with which this puzzling question might be 

 unlocked, but unfortunately for several months it was impossible 

 to replace the protozoa in the termites, once they had been thor- 

 oughly removed. Finally, a rapid and easy method of reinfection 

 was developed. Since the reinfection experiments are the most 

 important ones in the paper, perhaps, one of the seven which 

 were carried out, should be given in detail just as done and record- 

 ed in my note book. The other six are very similar to the one 

 recorded here. 



Ten large jars of termites were collected and were numbered 

 l-io/>45. Numbers i~7/>45 were incubated at 36 C. from 3:30 

 P.M., 10/21/22 to 3:30 P.M., 10/22/22. Numbers 8, 9 and 10/545 

 were not incubated and were left at room temperature (about 

 20 C.). Jars i~7/>45 were carefully examined on 10/23/22 and 

 the termites in them were found to harbor no protozoa. In 

 making this examination twelve individuals (workers), taken at 

 random from each jar, were carefully dissected and their entire 

 intestinal content painstakingly examined under the microscope 

 for protozoa. If no protozoa were found, the colony was labeled 

 "defaunated termites." Jar 6/745 was used as follows on 9/24/22, 



