58 MARY DRUSILLA FLATHER. 



rate shown in malted milk alone. The efficacy of malted milk 

 is due to the presence in it of both water-soluble B and fat 

 soluble A. Unpolished rice contains both but not enough fat- 

 soluble A for maintenance (6). 



Since orange juice is so potent a specific in the treatment of 

 deficiency diseases in man, a second set of experiments was 

 undertaken to see if when used with polished rice the accessory 

 food substances in orange juice would be an adequate substitute 

 for the rice vitamin. Parallel experiments were tried with un- 

 polished rice and malted milk to determine whether or not orange 

 juice would increase the metabolic activities of the organism in 

 media already known to be adequate for growth and maintenance. 



The orange juice was prepared by boiling I c.c. of orange juice 

 in distilled water and making up the solution to I per cent, after 

 evaporation. Previous trial experiments had been made with 

 different percentages of the orange juice, 5 per cent., I per cent., 

 2 per cent., and 3 per cent., and malted milk. The results 

 indicated that the I per cent, solution would be most favorable 

 for work with Paramecium. The races used for the special 

 problem were isolated from various sources, Pure line A was 

 identical with Pure line I of the first experiments, Pure line B 

 and Pure line C were isolated from cultures obtained from Powers 

 and Powers, Lincoln, Neb., and the University of Pennsylvania 

 respectively, Pure line D from a wild culture just introduced into 

 the laboratory, and Pure line E from a mixed culture kept in the 

 laboratory in hay infusion all winter. These gave a variety of 

 physiological conditions upon which to experiment. The indi- 

 viduals in Pure lines B and C were much larger and more vigorous 

 than those from the other lines. The wild race was especially 

 small but very vigorous after the firm establishment of the line, 

 while the races which had been kept in the laboratory all winter 

 were small and sluggish. Following the precautions observed 

 in the previous experiments, four individuals from each line 

 were isolated on April 22, 1918, one in two drops of distilled 

 water and one drop of I per cent, malted milk solution, a second 

 in one drop of distilled water and two drops of I per cent, malted 

 milk solution, a third in one drop of distilled water, one drop of 

 i per cent, malted milk solution and one drop of I per cent, orange 



