500 Profs. Percy Franklaiid and Marshall Ward. 



From the above tables it will be seen that the water-bacteria in the 

 deep well water underwent much more extensive multiplication 

 than in either the Thames or Loch Katrine water. This extensive 

 multiplication of the bacteria in such deep well water was first 

 called attention to by me in 1886 (' Proc. Roy. Soc.'). The in- 

 fected water must have contained, initially, about 28,000 typhoid 

 bacilli per c.c., and in this infected water the increase in the total 

 number of bacteria was. even more marked than in the uninfected, 

 the increase in the number of liquefying colonies being altogether 

 enormous. The behaviour of the typhoid bacilli in the sterile deep 

 well water (see p. 505) clearly shows that they cannot have partici- 

 pated in this bacterial multiplication observed in the infected ua- 

 sterilised deep well water, but on the contrary they must have un- 

 dergone great diminution, as it will be shown on p. 515 that the 

 typhoid bacilli were no longer discovered by phenol broth culture in 

 this water after 21.11.1893, or thirty -three days after their first intro- 

 duction. 



