FOOD REQUIREMENTS 511 



tures. I. The effect of -SH on Chilomonas Paramecium. Protoplasma, 20: 

 90-104. 

 — — 1934. Problems of population growth in the Protozoa. Cold Spring 

 Harbor Symp. Quant. Biol., 2: 167-80. 



1935a. Studies on the oxidation-reduction potential of protozoan cul- 

 tures. II. The reduction potential of cultures of Chilomonas Paramecium. 

 Arch. Protistenk., 86: 225-37. 



1935b. Studies on the physiology of the euglenoid flagellates. V. The 



effect of certain carbohydrates on the growth of Euglena gracilis Klebs. 

 Arch. Protistenk., 86: 238-50. 



1935c. Studies on the physiology of the euglenoid flagellates. VI. The 



effects of temperature and of acetate on Euglena gracilis cultures in the 

 dark. Arch. Protistenk., 86: 251-57. 



1935d. Studies on the physiology of the euglenoid flagellates. VII. 



The effect of salts of certain organic acids on growth of Euglena gracilis 

 Klebs. Arch. Protistenk., 86: 258-62. 



1936. Effect of aeration and lack of CO, on growth of bacteria-free 



cultures of Protozoa. Proc. Soc. Exper. Biol. N. Y., 33: 494-98. 



Johnson, D. F. 1935a.* The isolation of Glaucoma jicaria in bacteria-free 

 cultures, and growth in relation to pH of the medium. Arch. Protistenk., 

 86: 263-77. 



1935b. Fermentation of carbohydrates by Glaucoma and effects of 



carbohydrates on growth of two species. Anat. Rec, 64 (Suppl.) : 106-07. 



1936.* Growth of Glaucoma ficaria Kahl in cultures with single species 



of other microorganisms. Arch. Protistenk., 86: 359-78. 



Johnson, W. H. 1933.* Effects of population density on the rate of reproduc- 

 tion in Oxytricha. Physiol. Z06I., 6: 22-54. 



1936.* Studies on the nutrition and reproduction of Paramecium. 



Physiol. Z06I., 9: 1-14. 



1937.* Experimental populations of microscopic organisms. Amer. 



Nat., 71: 5-20. 



Johnson, W. H., and G. Mardin. 1938. Reproduction of Paramecium in old 

 culture medium. Physiol. Z06I., 11 : 333-46. 



Koser, S. A., and F. Saunders. 1938. Accessory growth factors for bacteria 

 and related microorganisms. Bact. Rev., 2: 99-160. 



Lawrie, N. R. 1937. Studies in the metabolism of Protozoa. III. Some prop- 

 erties of a proteolytic extract obtained from Glaucoma piriformis. Bio- 

 chem. J., 31: 789-98. 



Loefer, J. B. 1934. The trophic nature of Chlorogonium and Chilomonas. 

 Biol. Bull., 66: 1-6. 



1935a.* Effect of certain carbohydrates and organic acids on growth 



of Chlorogonium and Chilomonas. Arch. Protistenk., 84: 456-71. 



1935b. Effects of certain nitrogen compounds on growth of Chloro- 

 gonium and Chilomonas. Arch. Protistenk., 85 : 74-86. 



