MARY DRUSILLA FLATHER. 



TABLE I. 



THE DAILY RATE OF DIVISION. 



TABLE II. 



TOTAL OF DIVISIONS IN EACH GROUP AND AVERAGES. 



The graph shows that the division rate with polished rice is 

 broken and irregular, while that of the unpoKshed rice is fairly 

 regular and that of the malted milk very regular in daily in- 

 crease in the number of divisions. From these results it is 

 evident that unpolished rice is much less favorable than malted 

 milk as a culture medium for Paramecium, and that polished rice 

 is quite inadequate for maintaining the vitality of the organisms. 

 It seems probable that the essential factor lacking in the diet of 

 polished rice is the vitamin removed in the process of polishing. 



According to McCollum and Davis (4) polished rice is deficient 

 in fat-soluble A, and water-soluble B, the accessory food sub- 

 stances necessary for normal growth and maintenance of life. 

 The fats of rice contain very little if any fat-soluble A, while 

 all the water-soluble B is carried in rice polishings. In using 



