PROTOZOA AND OTHER ANIMALS 981 



That there is digestion of the starch has been well estabhshed (Trier, 

 1926; Westphal, 1934a, 1934b). Figures from Westphal (1934a) are 

 reproduced here (Fig. 207) showing successive stages in the rapid in- 

 gestion by Eudiplodinium medium in culture of rice starch and the dis- 

 solution of this. Although there seems to be no good reason for denying 

 starch-splitting ability to the ciliates themselves, Ullmann (1932) con- 

 sidered it possible that starch-digesting bacteria, taken in with the food 

 and continuing their action in the digestive vacuoles, are responsible. 



As starch is digested, glycogen (paraglycogen) accumulates in the 

 cytoplasm in granular form. The reserve material is stored in the ecto- 

 plasm, in the region of the gullet and the rectal tube, and sometimes 

 also in the endoplasm. It has been asserted by many that, in addition to 

 the other storage areas, the skeletal plates contain deposits of glycogen 

 (Schulze, 1924; Trier, 1926; Weineck, 1934; Westphal, 1934a, 

 1934b; MacLennan, 1934). Dogiel disagreed with this concept; and 

 Brown (MS), by a series of chemical tests, solubility tests with sub- 

 stances that would have been expected to extract glycogen, and enzy- 

 matic reactions, found no evidence that the contents of the skeletal 

 prisms is glycogen. Brown pointed out that the results of iodine reac- 

 tions are insufficient in themselves to identify glycogen, as other sub- 

 stances stain in the same way. 



Glycogen may be built up from simpler carbohydrates, appearing 

 after feeding with dextrose (Trier, 1926; Weineck, 1934) and lactose 

 (Trier). 



When, after deposits of glycogen have accumulated, the ciliates re- 

 main without food, the reserve is used up in cell metabolism. Trier 

 found that within forty-eight hours after ingestion of the starch most 

 of the accumulated glycogen had disappeared. 



There is disagreement as to whether the ciliates can use cellulose, 

 though certainly a quantity is ingested. Much quoted has been the state- 

 ment by Dogiel (1925) that, in the endoplasm of the Ophryoscolecidae, 

 cellulose pieces undergo no morphological change and leave by the 

 anus, still with sharp margins and no wrinkling or swelling. The state- 

 ment was evidently based on observations on Diplodinium maggii and 

 D. medium, which ingest large particles (Dogiel and Fedorowa, 1925). 

 Westphal (1934b) reported that he had confirmed this account of 

 ejection of large particles, but Weineck (1934) wrote that it has very 



