FURTHER STUDIES ON THE GEOTROPISM OF 

 PARAMECIUM CAUDATUM. 1 



SAKYO KANDA, 



THE PHYSIOLOGICAL INSTITUTE OF THE KYUSHA IMPERIAL UNIVERSITY, 



FUKUOKA, JAPAN. 



(With two figures.) 



CONTENTS. 



I. Introductory 108 



II. Material 109 



III. Experimental 109 



1. Specific Gravity of Paramecinm caudatum 109 



2. The Effects of Centrifugal Force on the Protoplasm of Paramecium 



caudatnm in 



3. Does Temperature reverse the Negative Geotropism of Parameciiim 



caudatum? 114 



4. Do Chemicals reverse the Negative Geotropism of Paramecinm 



caudatum? 117 



IV. Summary and Conclusion 119 



I. INTRODUCTORY. 



As evidence of the existence of proper mechanical conditions 

 in protoplasm as a basis for the "statocyst theory" of geotropism 

 in Paramecium, Lyon states: 'The animals were strongly cen- 

 trifuged for several minutes in the haematocrit attachment. 

 Microscopic examination showed that certian dark granules 

 originally distributed were now aggregated in one end, usually 

 the anterior. It is thus seen that differences in specific gravity 

 exist in the protoplasm of this animal." 1 In previous experi- 

 ments in which he attempted to test Lyon's results, the writer 

 "could obtain nothing definite"; and the tentative suggestion 

 was made that "immediately after centrifuging a capillary tube 

 containing Paramecia, and in which the latter can not turn around, 

 we may stain them with some dyes and determine the effects 



1 From the Physiology Laboratory of the University of Minnesota. 



2 Lyon, E. P., 1905, "On the Theory of Geotropism in Paramecium, Am. Jour 

 Physiol, Vol. 14, p. 430. 



108 



