15% aged sea water) and (2) peptone sea water agar (peptone sea 

 water plus 1.5^ bacto-agar) . These media as well as all other 

 sterility testing media subsequently described were dispensed in 

 screw-oap tubes and autoclaved at 121° C. for 15 minutes. 



We frequently used four other media similar to those employed 

 by Droop (1954-) for routine sterility testing. These media 

 included: (l) distilled water liquid, (2) distilled water agar, 



(3) sea water liquid, and (4) sea water agar. Our media contained 

 the following substances: 0.5^ dextrose, 0.1^ Difeo neopeptone, 

 0.4^ bacto-beef extract, 0,5^ bacto-yeast extract, 0,015^ sodium 

 acetate (NaC2H302.3H20), and soil extract (2.0 ml/lOO ml). These 

 substances (dextrose was often excluded) with and without -.bacto- 

 agar (1.5^) were dissolved in both distilled water and 75^ aged 

 sea water to give the four combinations mentioned above. Droop 

 (1954) listed the substances but not the quantities used. A personal 

 communication (1956), however, revealed that his formula contained 

 the organic substances in concentrations which were roughly 10 



to 15 times less than the quantities given above. Furthermore, 

 he included bacto-tryptone, which was not listed in his paper 

 whereas we used Difco neopeptone. Subsequent to the completion of 

 the present studies, the absence of bacteria from several G. brevis 

 cultures was confirmed with media of Droop's formulation and also 

 with these media diluted to 10 percent. 



Other media used to supplement the routine tests included: 



(1) the sterility-test medium used by Sweeney (1954) containing 

 0.05^ bacto-peptone, 0,0136^ sodium acetate (NaC2H302.3H20) , 

 0.0202^ KNO3, 0-00356^ K2HP0^, 0.00016^ FeCl3.6H20, and 0.000012^ 

 MnCl2"6H20 dissolved in 75^ aged sea water with and without bacto- 

 agar (1.5^); (2) Spencer's peptone sea water media supplemented 

 with 0.1^ bacto-yeast extract as employed in medium 2116E (Morita 

 and ZoBell, 1955); (3) semisolid medium composed of 0,075^ trjrpti- 

 case (Baltimore Biological Laboratory), 0.075^ bacto-peptone, 

 0.075^ bacto-yeast extract, 0.01^ sodium acetate (NaC2H302.3H20) , 

 and 0.2^ Difco special (Noble) agar dissolved in aged sea water; 



(4) one percent bacto-peptone in aged sea water with and without 

 bacto-agar {1.5%), the medium used by Bein (1954) "t® isolate and 

 cultivate certain chromogenic bacteria found in Florida waters ; 

 and (5) Spencer's (1952) casein sea water agar composed of 0.05^ 

 bacto-peptone, 0,05^ bacto-isoelectric casein, 0.05^ soluble starch, 

 0.1^ (v/v) glycerol, 0,02^ K2HP0^, and 1.5^ bacto-agar dissolved 



in 75^ sea water. 



Sterility tests for anaerobic bacteria were conducted occasionally 

 with three different media: (l) bacto-fluid thioglycollate medium 

 rehydrated with both distilled water and 75^ aged sea water; 



(2) the general anaerobic mediiim (slightly modified) used for marine 

 bacteria by Morita and ZoBell (1955) containing 0,5^ bacto-peptone. 



