SIX FIGURES
Ciliates of the genus Stenfor, like other protozoa (review: MacLennan, '41), contain fluctuating amounts of carbohydrate nutritional reserves. This material is granular and may be seen in the living cell ; its precise location and migrations can be followed without the disturbances of fixation and staining. Adaptability of stentors to cutting operations permits one to test the effects of excision of the glycogen-like reserves on regeneration and survival.
Zhinkin ('30) first demonstrated carbohydrate as well as f a t reserves in Stentor polpnorphus and S. coeruleus by specific staining of whole-mounts and sectioned material, noting that the carbohydrate tends to concentrate at the posterior end of the cell, is stored during periods of abundant feeding and used up during starvation. His observations also suggest that carbohydrate reserves ( CHOr) are accumulated through increase in number and size of the granules at lower temperatures and higher oxygen tensions ; the situation with reference to fat was the reverse. At freezing temperature the fat presumably increases at the expense of the carbohydrate. The greatest CHOr was found in stentors collected in the autumn and the most fat in winter stentors under ice. Carbohydrate reserves soon disappeared from autumn stentors brought into the laboratory and this observation led