A SUMMARY OF THE RESULTS OF CERTAIN PHYS- 



lOLOGICAL STUDIES ON A PEDIGREED 



RACE OF PARAMAECIUM* 



LORANDE LOSS WOODRUFF 

 (Sheffield Biological Laboratory, Yale University) 



(With plate 6) 



The free-living Protozoa of the group Infusoria lend them- 

 selves in an admirable manner for experimental studies in general 

 physiology. As unicellular animals they represent the organism 

 reduced to its simplest term, and therefore many complications 

 which arise in the study of physiology in the metazoan cell-state 

 are greatly reduced, if not entirely ehminated. However, although 

 research in the physiology of the Protozoa has thus far been pro- 

 ductive of certain fundamental and far-reaching conclusions, one 

 must confess that the results secured have not fulfilled the expecta- 

 tions in regard to many perplexing problems whose Solution seemed 

 comparatively easy of attainment in these lowest animal forms. 

 This condition is not due to lack of endeavor to solve the riddles 

 which they hold, but to an earlier inappreciation of their complexity. 

 The wealth of literature on the Protozoa emphasizes above all the 

 fact that, while they are the simplest, they are by no means simple 

 animals. 



The purpose of the present paper is to present a brief resume 

 of certain results which have been secured to the present time from 

 physiological studies on a pedigreed race of Parmncecüim aurelia 

 which I have had under daily Observation for more than four and 

 one years (cf. plate VI). 



This culture of Paramcecium was started on May i, 1907, with 

 a "wild" individual which was found in a laboratory aquarium. 

 The original specimen was placed in about five drops of culture 

 medium on a glass slide having a central ground concavity, and 



* Read before the Yale Biological Club, December 7, 191 r. 



396 



