ROTH OH \M \i:< II' I \< I l I IOLOOY. 



143 



These cultures were n> ad- \\ ati n few drops of the surface water taken some distance 

 from the shore, the temperature of the water at this season varying between 29* F. and 83* F. 

 Incubation was carried out by keeping the tubes in Oinon<l II. MI-.-, where the temperature 

 varied between 45 K. and tin !'. The gelatine was in the form of sloped tuba*. 



Seven of the ten cultures yielded growths, three did not. It is probable that the 

 number of bacteria in Antarctic sea water cajtable of growing on ordinary nutrient media 

 is comparatively small It may be mentioned that Dr Ekeldf from his quantitative 

 observations f<>un<l on an average 4'4 organisms per c.c., and never more than 21. 

 Dr Gazert, on the German Expedition, from to 10 per c.c. A few cultures brought 

 home by Dr Charcot yielded two coccal forms, three species of bacilli, and two yeast or 

 Tornln forms. From their description I am inclined to regard the organisms I observed 

 aa very similar forms. Dr Ekelof isolated five different species, all spirillar or bacillary 

 forms. I have not yet seen Dr Gaxert's full report, so am unable to say what was the 

 character of the organisms he obtained. 



(b) A Number of Examinations of Surface Sea Water made to ascertain whether 

 Denitrifying Organisms were present or not. The folloiriny media were used 

 for this purpose. 



The observations were all made on surface waters from various localities in the 

 Weddell Sea during the first summer's cruise in 1903. The surface water tem|>eratures 

 at this time were all between 29 F. and 30 F. The inoculated tubes were, as a rule, 

 kept at first in the laboratory, where the temperature varied between about 35 F. and 

 55 F. ; but as it was found that very little growth or denitrification occurred, they were 

 later transferred to a temperature kept more or less steadily about 60 K. 



The following brief notes taken from my notebook regarding a few of these may be 

 taken as fairly typical of the whole : 



No. 2. Medium B. Contains a small motile bacillus occurring sometimes in short 

 chains. 



