Action of Pancreatic Vitamine. 



four hours when the culture was again examined and the number 

 of individuals counted to get the number of divisions. The 

 control individual was isolated in an identical medium but without 

 the fuller's earth. Five double sets prepared and examined in 

 this way were carried on for a period of 10 weeks. 



Experiments. 



1. In the first series of experiments the organisms were kept 

 in their usual medium of hay infusion and the vitamine-bearing 

 fuller's earth was added to this. Five lines of experimental 

 animals and five of controls were carried on for 5 days giving 

 27 divisions in the control series and 26 in the vitamine set. The 

 results were therefore entirely negative. 



2. In the second series boiled flour was substituted for boiled 

 hay. Five sets of control Paramecium and five sets treated with 

 vitamine were carried along for 15 days. The results may be 

 best considered in three groups covering 5 consecutive days each, 

 as follows: 





Controls. 



Vitamine-treated, 



Divisions. 



Rate. 



Divisions. 



Rate. 



Group A. First 5 days 



27 



1.08 



32 



1.28 



Group B. Second 5 days 



12 



O.48 



22 



0.88 





21 



O.84 



24 



0.96 



Totals 



60 



0.80 



78 



1.08 



Here with organisms of different grades of vitality there is a very 

 slight increase in the division rate of the vitamine group, but not 

 enough to prove that the vitamines were effective in stimulating 

 nutrition. 



3. In both of the preceding series, individuals were taken at 

 random from a culture dish. While all came from the same 

 original individual it was impossible to tell whether young or 

 old individuals were isolated. In this third series of tests this 

 objection was overcome by using sister cells, one for control, the 

 other for vitamine treatment. In this experiment, as in the 

 others, five lines of control animals and five of vitamine-treated 

 animals were carried on, this time for a period of thirty days, 



