Report on the Bacteriology of Water. 543 



In this series of experiments the influence of rest or agitation 

 was also studied. 



(Description of experiments, see pp. 493 et seq. ; summary of con- 

 clusions, pp. 516 518.) 



7. A series of experiments made in order to ascertain whether tho 



bactericidal properties of unsteriltsed surface water can be 

 artificially induced by inoculating steam-sterilised Thames 

 water with a few drops of unsterilised Thames water, and 

 thus giving rise to a bacterial population in the previously 

 sterile water. 



(Description of experiments, see pp. 519 et seq. ; summary of con- 

 clusions, pp. 528 530.) 



8. Further experiments on the addition of common salt to typhoid- 



infected Thames water, both sterile and unsterile, with a view 

 to confirming or contradicting the results of the experiments 

 referred to under No. 3 above. 



(Description of experiments, see pp. 530 et seq. ; summary of con- 

 clusions, pp. 535 536.) 



9. Experiments made to ascertain whether the typhoid bacillus 



and the Bacillus coli communis, multiply in potable water which 

 is very highly charged with vegetable matter (peaty, upland, 

 surface water). 



(Description of experiments, see pp. 536 et seq. ; summary of con- 

 clusions, p. 538.) 



10. Experiments made to ascertain whether the typhoid bacillus 



can, by prolonged preliminary culture in more and more 

 diluted media, be trained for aquatic life in potable water. 

 (Description of experiments, see pp. 539 et seq. ; summary of con- 

 clusions, p. 541.) 



For the detailed conclusions arrived at from the results of these 

 several series of experiments, the reader is referred to the summaries 

 which are appended to the descriptions of each series of experiments, 

 as indicated above, whilst the general conclusions which arise out of 

 the entire investigation may -be summarised as follows : 



Summary of Conclusions. 



1. Typhoid bacilli from ordinary agar-agar- and gelatine-cultures 

 on being introduced into steam-sterilised potable water in such num- 

 bers as not to materially alter the composition of the latter undergo 

 TIG multiplication. This result was uniformly obtained irrespectively 

 of whether surface water like that of the Thames, which has received 

 the drainage of manured land, or upland surface water like that of 

 Loch Katrine, the organic matter in which is very similar in absolute 



