2i6 Proceedinqs Columbia Biochemical Association [March, 



of reduction. He also observed that sodium selenite, even in very 

 small conc, inhibited growth, whereas sodium sulfite favored it. In 

 the 1910 editionof Kruse's Allgemeine Mikrobiologie, the Statement 

 was made that anerobes do not seem to reduce sodium selenite, as 

 indicated by the few preliminary findings of Klett. 



In Order to test the validity of this conclusion, experiments with 

 sodium selenite were made with anerobes available in the bacterio- 

 logical collection at the Museum of Natural History.^^ The follow- 

 ing organisms were used: B. Welchi (four strains) ; B. sporo genes 

 (three strains) ; B. Feseri (two strains) ; B. oedematis maligni (two 

 strains) ; B. tetani (two strains) ; B. oedematis; B. hotidinis; B* 

 putrificus. They were grown in media containing the following 

 conc. of sodium selenite : i : 100,000; i : 50,000; i : 25,000; i : 10,000. 

 The culture tubes were kept under anerobic conditions by means of 

 alkalin pyrogallate. 



No appreciable inhibition of growth was observed except in conc. 

 of 1 : 10,000. Reduction was found to have taken place within 24 

 to 48 hr. in conc. of i : 100,000, but the red selenium streak follow- 

 ing the path of growth disappeared within a few days, so that there 

 was no visible evidence of reduction. The higher selenite conc. 

 showed excellent reduction but there was less tendency for the 

 red precipitated selenium to disappear. At the end of 3 months the 

 selenium streaks had completely disappeared in all the culture tubes 

 except in the ones containing sodium selenite in conc. of i : 10,000. 



These experiments prove conclusively that aerobes and anerobes 

 reduce sodium selenite equally well and that sodium selenite cannof 

 be used as a reagent for differentiation between these two classes of 

 micro-organisms. For practical demonstrations, conc. of i : 25,000 

 and 1 : 10,000 yield the best results. 



164. Body surface and metabolism of flounders. Sergius 

 MoRGULis (U. S. Fisheries Biological Station, Woods Hole, 

 Mass.) In connection with various biological problems the impor- 

 tance of the body surface has been frequently emphasized. Never- 

 theless, owing to the difficulties involved in measuring the surface 

 of an organism, knowledge on this score has been very fragmentary. 

 The flounder is an unusually favorable object for an investigation of 



15 Levine : Biochem. Bull., 1914, iii, p. 464. 



