30 THE ROYAL SOCIETY OF CANADA 



separation of calcium carbonate will then depend on the new equili- 

 brium set up between the base produced and the carbonic acid in 

 solution. It is clear that under these conditions calcium carbonate 

 may be precipitated from the bicarbonate already in solution, quite 

 apart from fresh CO2 introduced into the system by the vital activity 

 of organisms. It is very doubtful, however, whether the production 

 of ammonia would go on sufficiently rapidly in the open sea to neutralize 

 the carbonic acid in solution, except perhaps in the immediate neigh- 

 bourhood of a mass of decaying organic material, in which case the 

 reaction may also be a factor in the production of calcareous fossil 

 casts. Denitrification, to any significant extent, appears to be a factor 

 in this connection only in special cases and in warm seas. It should 

 be borne in mind, too, in considering the question from the geological 

 standpoint, that in the deep sea, though conditions may conceivably 

 be such as to lead to the bacterial production of calcium carbonate at 

 or near the surface, where, due to both temperature and pressure, the 

 concentration of carbonic acid is relatively low, it would probably 

 be redissolved at depths where the concentration was greater. 



The case studied by Drew seems to have been one of a somewhat 

 special nature in which, not only were denitrifying organisms prevalent 

 in the sea, but also the concentration of carbonic acid was low, due to 

 its high temperature and comparatively small depth, and that of 

 calcium salts high, due to the draining into the sea of a heavily wooded 

 country with a calcareous subsoil. 



Ammonification 



The power of producing ammonia from complex organic nitro- 

 genous substances is one very commonly possessed by bacteria. The 

 usual method of testing for it is to inoculate into a medium containing 

 Peptone in solution and to test the culture with Nessler's Reagent 

 after incubation. This method was employed here, the medium used 

 being a -2 per cent solution of Peptone in sea- water. This medium 

 was neutral and contained only a trace of ammonia. Flasks contain- 

 ing 25cc. of it were inoculated with -Sec. of each sample of sea-water; 

 three were kept at 28°C and three at air temperature and a "blank" 

 kept under like conditions in each case. As in the case of the denitri- 

 fication cultures the flasks inoculated with the 20 fathom and 100 

 fathom samples and kept at 28°C failed to show any growth. The 

 flask inoculated with the surface sample and kept at this temperature 

 developed a heavy flocculent growth after 2 days. The growth had a 

 peculiar "woolly" appearance exactly like that which had been seen 

 all through the sea when the sample was taken. So remarkably like 



