222 L. R. CLEVKI.ANT). 



passed by Teredo navalis, and, as a result of the analyses, these 

 investigators conclude that "the wood lost about 80 per cent, of 

 its cellulose, and from 15-56 per cent of its hemicelluloses, in- 

 cluding from II to 40 per cent furfural yielding constituents such 

 as pentosans, etc.," during its passage through the animals' 

 digestive tracts. They state further that "The simplest explana- 

 tion of the disappearance of this carbohydrate material is that 

 the cellulose and hemicelluloses of wood are partly digested by 

 the teredo and probably hydrolyzed to simple carbohydrates 

 which the animals can use." In all these investigations it should 

 be noted that many substances other than cellulose were present. 

 In no instance was cellulose alone fed the animals. It would be 

 very interesting, indeed, to study the microorganisms of these 

 crustaceans and mollusks. No mention is made by these investi- 

 gators regarding the possibility of microorganismal cellulose 

 digestion. 



Recently a cellulose-digesting anaerobic bacterium has been 

 isolated from 60 per cent of the human stools examined (Khou- 

 vine-Delaunay, 1922), and it is quite possible that future re- 

 searches will reveal that intestinal microorganisms perhaps play 

 a more important part in cellulose digestion than has previously 

 been thought. Intestinal bacteria and fungi quite often aid their 

 vertebrate and invertebrate hosts in the digestion of cellulose and, 

 since it has been shown in the present investigation that intestinal 

 protozoa can digest cellulose, it is now possible that the Infu- 

 soria, such as Diplodiniiim, Entodinium, Bittschlia, Isotricha, 

 Dasytriclia and Ophryoscolex, harbored by ruminants, notably the 

 ox, goat, sheep, camel and reindeer, may aid their hosts in the 

 digestion of cellulose and hemicellulose. The Equidre also harbor 

 similar Infusoria. 



GENERAL SUMMARY. 



1. There are four families of termites and all the species and 

 genera of three of them, Kalotermitidae, Rhinotermitida? and 

 Mastotermitida?, that have been examined have been found to 

 harbor enormous numbers of intestinal protozoa. No termite of 

 the other family, Termitida?, has been found to harbor intestinal 

 protozoa. 



2. The principal food of protozoa harboring termites is wood 

 and the principal compound in the wood which the termites use 



