1886.] On the Multiplication of Micro-organisms. 543 



Finkler-Prior's Spirillum in Sewage. 

 Number of Colonies obtained from 1 c.c. 





1st Day. 



2nd Day. 



4th Day. 



5th Day. 



9th Day. 





390 















to 2 



390 















„ 3 



390 















» 4 



10,750 

















„ 5 



10,750 

















Note. — Nos. 3 and 5 were placed in the incubator. 



From the differences which these three organisms present in their 

 behavionr in water, and in different kinds of water, it is evident how 

 fallacious must be any conclusions as to the vitality of pathogenic 

 micro-organisms in general, more especially when such conclusions are 

 based upon observations made with organisms which are the natural 

 inhabitants of natural waters, as has often hitherto been the case. It 

 is obvious that each individual organism must be made the subject of 

 separate investigation as to its vitality. To render such investiga- 

 tions complete, it is necessary also that the organisms under examina- 

 tion should be taken from different sources, as from the experiments 

 which I have quoted in the case of the comma Spirilla it is evident 

 that an initial weakness of the growth from which the inoculation is 

 made renders the organisms less capable of withstanding the con- 

 ditions of the experiment. It would also appear probable that this 

 initial difference in vitality may be the cause of some of the many dis- 

 crepant results which have been obtained by different observers in the 

 study of antiseptic action. That there exists a difference in resisting 

 power according to the virulence or initial vitality of the organisms 

 themselves has already been drawn attention to by Dr. Klein 

 ("Micro-organisms and Disease," 1886). 



In the following table the chemical composition of the sewage and 

 other waters employed in the above experiments is recorded : — 



