20 



ROYAL SOCIETY OF CANADA 



the St. Lawrence and Ottawa is very constant throughout the year, and 

 as the difference between the alkalinity of two .rivers is marked, calcula- 

 tions as to the percentage of Ottawa and St. Lawrence waters as found 

 in the aqueduct water of the city of Montreal at diffeient months may 

 easily be made. Dr. Euttan thinks his results are very satisfactory and 

 give a very fair estimate of tl\e proportion of Ottawa Eiver and St. 

 Lawrence Rive.r waters that find their way into the Montreal water supply 

 during the year 1904-1905. 



Percentage of Ottawa River and St. Lawrence River Waters in 

 Montreal Water Supply, 1904-5. 



St. Lawrence River. 



23.60 43.5 39.3 



89.9 95.6 



6.3 



10.0 



50.0 



71.5 



64.0 



65.8 



57.8 



The average for the year is 48 per cent and 52 per cent, respectively, 

 and presuming that the Ottawa water retains its B. coli content for 

 some 15 miles beyond Ste. Anne's, the water used in the city of Montreal 

 would contain about the same numbers of B. coli as are shown in Table 

 I. According to modern sanitary standards, such water should be in- 

 admissible as a source of supply, unless subjected to preliminar)'^ treat- 

 ment. 



Experiments on the Duration of Life of B. coli in Ottawa 



River water. 



Jordan ^ has already pointed out that B. coli may be recovered 

 from sewage and polluted river water that has been stored in the 

 laboratory for some weeks. Horrocks ^ recovered B. coli which had been 

 placed in flasks of well water and river water kept at room temperature 

 for three months. The organism recovered was more feeble in its indol 

 formation power as compared with the original culture. 



As some investigators (Hankin, Russell) have noticed the bacter- 

 icidal powers of certain river or lake waters it seemed advisable to carry 

 out a number of experiments on the duration of life of B. coli in Ottawa 

 River water. 



