THE GROWTH OF PARAMECIUM IN PURE CULTURES 



OF BACTERIA 



GEO. T. HARGITT AND WALTER W. FRAY 



From the Zoological Laboratory of Syracuse University 



INTRODUCTION 



Paramecium has long been a favorite form for studies of 

 various kinds, and with justice since it is of considerable size, 

 is composed of a single cell, is easily obtained, and is easily 

 maintained in vigorous condition in cultures ijn the laboratory. 

 Some of the factors which are involved in the cultivation of 

 Paramecium have been carefully studied with the result that 

 we have rather complete and precise data on their significance. 

 This analysis includes not only some of the biological factors 

 involved in the activities and functions of the infusoria, but 

 some of the chemical and physical factors of hay infusions and 

 culture fluids. 



One of the biological factors of importance is the food of 

 Paramecium. It has long been known that bacteria furnish 

 the chief food supply, and in some of the most careful work 

 attempts have been made to secure a uniformity of food, with 

 some measure of success. It is, however, rather striking that 

 not a single effort has been made by modern methods to analyze 

 the hay infusion bacteriologically. This failure is the more 

 striking in view of the known fact that lack of vigor in cultures 

 and certain 'depression' states, are doubtless due to something 

 unfavorable in the food supply. Also th^ conclusions of much 

 of the modern work on Paramecium may be significant to the 

 degree that the factor of food is understood, and under control. 



Recognizing this gap in our knowledge of one of the most 

 essential factors touching the life of Paramecium we have, dur- 

 ing the past year, made a start on a bacteriological analysis of 



421 



