PHYSIOLOGY 105 



centrifuged Pelomyxa carolinensis comparatively evenly distributed 

 after centrifugation, possibly with a tendency to be concentrated in 

 the lighter half, while proteinase was largely localized in the heavier 

 half in which cytoplasmic granules were accumulated, and concluded 

 that these two enzymes are bound, at least in part, to different cyto- 

 plasmic components. A number of enzymes have been reported to 

 occur in Protozoa, some of which are listed in Table 3. 



These findings suffice to indicate that the digestion in Protozoa 

 is carried on also by enzymes and its course appears to vary among 

 different Protozoa. The albuminous substances are digested and de- 

 composed into simpler compounds by enzymes and absorbed by the 

 surrounding cytoplasm. The power to digest starch into soluble 

 sugars is widely found among various Protozoa. It has been re- 

 ported in Mycetozoa, Foraminifera, Pelomyxa, Amoeba, Enta- 

 moeba, Ophryoscolecidae and other ciliates by several investigators. 



The members of Vampyrella (p. 420) are known to dissolve the 

 cellulose wall of algae, especially Spirogyra in order to feed on their 

 contents. Pelomyxa (Stole), Foraminifera (Schaudinn), Amoeba 

 (Rhumbler), Hypermastigina, Polymastigina (Cleveland), etc., have 

 also been known for possessing the power of cellulose digestion. 

 Many of the Hypermastigina and Polymastigina which lead symbi- 

 otic life in the intestine of the termite and of the wood roach, as dem- 

 onstrated by Cleveland and his co-workers, digest by enzymes the 

 cellulose which the host insect ingests. The assimilation products 

 produced by an enormous number of these flagellates are seemingly 

 sufficient to support the protozoans as well as the host. The cili- 

 ate commensals inhabiting the stomach of ruminants also appar- 

 ently digest the cellulose, since the faecal matter as a rule does not 

 contain this substance (Becker et al., 1930; Weineck, 1934). 



Dawson and Belkin (1928) injected oils into Amoeba dubia and 

 found 1.4 to 8.3 per cent digested. Mast (1938) reported that the 

 neutral fat globules of Colpidium are digested by Amoeba proteus 

 and transformed into fatty acid and glycerine which unite and form 

 neutral fat. Chen (1950) found that when Peranema trichophorum 

 was fed on almond oil (stained dark blue with Sudan black), Sudan 

 III-stainable droplets gradually increased in number in five to 10 

 hours, while ingested oil-droplets decreased in size, and considered 

 that the droplets were "fat-substances" resynthesized from prod- 

 ucts of digestion of almond oil by this flagellate. The digestion of 

 rice starch is followed by the appearance of increasing number of 

 ovoid paramylon granules, and the digestion of casein results in the 

 formation of oil droplets and paramylon bodies. 



