536 Profs. Percy Franldand and Marshall Ward. 



far as I am aware, such abnormally formed typhoid colonies 

 have not been previously observed, and I am inclined to 

 attribute them to the degeneration of the typhoid bacilli, for, 

 on passing such colonies through a further process of plate 

 cultivation, only the normally formed typhoid colonies were 

 obtained. 



On the _ Possibility of the Typhoid Bacillus or the B. coli communis 

 multiplying in Potable Water. 



In none of the several series of experiments with Thames, Loch 

 Katrine, and deep well (chalk) water, already recorded, was there any 

 evidence of the typhoid bacillus undergoing any multiplication 

 whatsoever ; on the contrary, in all cases in which the typhoid bacillus 

 was introduced into these waters in a sterilised condition there was a 

 more or less rapid diminution in its numbers observed. In the case 

 of the B. coli corn-munis, in the steam-sterilised Thames water (p. 454), 

 there was considerable multiplication of the B. coli communis observed 

 when the water was kept at a summer, but practically none when it 

 was maintained ac the winter, temperature; on the other hand, in the 

 steam-sterilised Loch Katrine water (see p. 481) the B. coli communis 

 did not exhibit any numerical increase, but, on the contrary, rapid 

 decline. 



Of the waters experimented with above, the Thames water contains 

 about the average quantity of organic matter present in those surface 

 waters from cultivated land which are supplied for domestic purposes, 

 whilst similarly the extremely small proportion of organic matter in 

 the Kent well water is typical of the water supplied from deep 

 wells ; on the other hand, the Loch Katrine water contains decidedly 

 less organic matter than is usually present in the water supplied to 

 towns from upland surface sources. Now, although the experiments 

 which have been detailed above conclusively show that the typhoid 

 bacillus does not proliferate in the Thames, deep well, or Loch 

 Katrine water employed, it appeared to me to be of importance to 

 ascertain whether in upland surface water, more highly impregnated 

 with organic matter than is the case with that from Loch Kati-ine, 

 such proliferation of the typhoid bacillus might not perhaps take 

 place. 



For this purpose I employed, as specially fitted for the object in 

 view, some moorland suo-face water which is supplied to a large manu- 

 facturing population in North Britain, and which the following 

 analysis shows is very highly charged with organic matter of a peaty 

 character : 



