INTESTINAL PROTOZOA OF TERMITES. 223 



is cellulose. This was demonstrated by keeping termites alive 

 and active indefinitely on a cellulose diet. 



3. The protozoa harbored are all killed off by incubation at 

 36 C. for 24 hours, while the termites apparently are not injured 

 at all by the incubation. 



4. The incubated and defaunated (with the protozoan fauna 

 removed) termites die within 10-20 days, on the average, after 

 incubation, if fed tlu-ir normal diet of wood. 



5. When the incubated and defaunated termites are fed di- 

 gested wood (e.g.,humus) or fungus digested cellulose, they live 

 indefinitely. 



6. The ilr.ith of the incubated and defaunated termites is not 

 dm- to the. incubation t>cr se, but to an inability to digest wood. 



7. When the incubated and defaunated termite- are rein- 

 IV. ted with pro 1 'heir ability to utilize wood, their normal 

 diet, reap; Mid they live indefinitely. 



8. The reni-Aal, then, of the protozoa seem- to In- tv-poii>ible 

 for the loss of the ability to utilize wood as fc.nl. l'o determine 

 this i|ue-tion the ability of the bacteria, fungi and protozoa, 

 harbored bv termites, to digest wood or pure cellule-^- w.i- care- 

 fully >t in lied. It was loinul that the bacteria and fungi could not 

 digest cellulo-e, but that some of the protozoa could. 



.). Now, -in- e the termites die in 10-20 days, if fed a \\ 1 diet , 



after the pi"io/oa have been removed from them bec.iu-e they 

 cannot dige-t their food (wood), as shown by the fact that they 

 do not die, but live indefinitely, when fed digested WO.M) <ir when 

 reinfei ted \\ith protozoa and fed wood, and >ince the proto/<>a 

 do digest tin- \\ccd particles which they take into their bodie-, it 

 i> highly probable, if not certain, that the termites are dependent 

 on the plot../, i.i t.. digest their food for them. 



to. Net all of the protozoa harbored by Retictditennes flavipes 

 dLe-t \\ood particles. Some of them either live at the expense of 

 the wccil dke-ting protozoa or their host, or both. 



II. The proio/oa receive from the termite- food and lodging, 

 for which they give in return protozoal wood digestion products. 



u. The relationship between some of the protozoa, particu- 

 larly Trichonympha and Pyrsonympha, and their host, Rt'licnli- 

 termes flavipes, is one of s 



