THE EFFECTS OF A DIET OF POLISHED AND OF 

 UNPOLISHED RICE UPON THE METABOLIC 

 ACTIVITY OF PARAMECIUM. 1 



MARY DRUSILLA FLATHER. 



The purpose of the following experiments was to discover the 

 effects of the presence and absence of the vitamin contained in 

 rice upon the metabolic activity of Paramecium.. It was suc- 

 cessfully proved by Funk (2), that the vitamin which prevents 

 the deficiency disease known as beri-beri in man is removed from 

 the rice by'the process of polishing. Since the lack of this vitamin 

 in the diet of human beings produces a seriously diseased condition 

 it seemed a promising subject for research to determine whether 

 o*- not the effects could be so far-reaching as to alter the meta- 

 bolism of a one-celled organism, Paramecium. Calkins (i) had 

 previously shown that pancreatic vitamin, a specific in the case 

 of marasmus, had no influence whatever upon 'the metabolic 

 activities of Paramecium. Calkins used the division rate as 

 an index to the vitality of the organism, believing that certain 

 substances in the culture medium may increase the rate of div- 

 sion and others decrease it. This criterion is the one used in the 

 following investigation. 



The experiments were performed upon individuals from five 

 pure lines, all from wild cultures started in the laboratory at the 

 same time and kept in spring water and hay infusion for one 

 month. The pure lines were started on December 4, 1917. 

 Each individual was isolated in three drops of distilled water 

 and one drop of I per cent, malted milk solution, renewed every 

 other day. The malted milk was prepared by pouring 50 c.c. 

 of boiling distilled water over .5 gram of Horlick's malted milk. 

 After several divisions had taken place each pure line was trans- 

 ferred from the depression slide to a large stock dish containing 

 200 c.c. of distilled water and 5 c.c. of malted milk solution. 

 Once a week one half of the stock solution was removed and an 



1 From the Biological Laboratory of Bryn Mawr College. 



54 



