Report on the Bacteriology of Water. 



391 



~ m M o 



MO 90 9-30 KM) (0-30 ll-O 1-30 12-0 1^50 1-0 1-30 M 



The growth had entirely ceased, as I convinced myself by nursing 

 the culture in the incubator for the rest of the day. 



Whether this was due entirely to the loss of oxygen brought about 

 by the form ft, which showed beautiful chemotactic aggregations 

 about the filaments, by the bye or to other causes brought about by 

 the action of the intruder, cannot be with certainty determined, but 

 it is obviously a line of enquiry worth further pursuit. In any case 

 the shape of the curve is entirely different from the usual one, and 

 fully supports the conclusion that the intruding bacterium was robbing 

 the filaments of oxygen. 



The observation is of considerable interest as touching the ques- 

 tions of antagonism and chemotaxis, and it is probable that the 

 subject would well repay investigation. I had to refrain from 

 pursuing the matter further, however, and merely give this case 

 not the only one of the kind that has come under my notice owing 

 to the necessity of following the special line of research I was 

 engaged in. 



Effect of probable Poisonous Action. 



The following is quoted as probably a case of the poisonous action 

 of some product of combustion of the over-heated cotton-wool in the 

 arms of the cell. It is not certain that the action was what I suppose, 

 but it is suggestive that all the filaments in the drops were suffering, 

 whence may be safely inferred that some common action was 

 going on. 



On November 11, spores were sown exactly as before, in normal 

 gelatine, at 10.45, at 22 C. : at 4 P.M. the measurements were started 

 at 25 C. 



