PARAMECIUM IN PURE CULTURES OF BACTERIA 



443 



TABLE 5 



Paramecium aurelia grown in pure cultures of bacteria, in 0.1 per cent hay infusion. 

 Figures represent number of divisions; * dead; ^ animal abnormal 



Bacterium I. . 

 Bacterium I. . 

 Bacterium II. 

 Bacterium II. 



Sterile water. 



27 



28 



29 



Mixed bacteria. Several lines, for 12 day.s, averaged: 



TOTAL 

 DIVI- 

 SIONS 



1 1 11 



(still alive) 7 

 9 

 6 



21 



AVER- 

 AGE DI- 

 VISIONS 

 PER DAY 



JO. 916 

 0.875 

 0.818 

 0.857 



1.749 



TABLE 6 



Paramecium caudatum grown in pure cultures of bacteria, in 0.1 per cent hay infu- 

 sion. Figures represent number of division; ^ deads; ^ animal abnormal in some 

 way. 



AVER- 

 AGE DI- 

 VISIONS 

 PER DAY 



Bacterium I. . 

 Bacterimn I. . 

 Bacterium II. 

 Bacterium II. 

 Sterile water. 

 Sterile water. 



0.250 

 0.666 

 0.333 

 0.600 



1.083 



The data show that Paramecium will live for some time in 

 the total absence of food, and may even divide when in a me- 

 dium of sterile water; in the cases recorded 2 days, 5 days, 6 

 days was the period of life in sterile water. In only one of these 

 cases was there a division, and this must have been due to 

 reserve food in the body, or possibly to the absorption of water. 

 A second conclusion from the records is that the rate of fission 

 is noticeably reduced, considerably in the case of P. caudatum, 

 not so much in P. aureUa. More significant than the reduc- 



