218 Transactions of the Society. 



a large quantity of organic matter in the Mater one mi-lit 

 naturally expect that it would inhibit the action of the hypo- 

 chlorite upon the bacteria. Let us see what happens in water 

 containing this large quantity of organic matter. If sufficient 

 hypochlorite be added t<> give a very large excess of chlorine at 

 the end of twenty minutes, and samples of this treated water be 

 tested at intervals of three or four hours, it will be found that the 

 whole of the " chlorine " may have disappeared in twenty-four or 

 forty-eight hours, the oxygen being used up as it is set free 

 (nascent) in oxidizing the organic matter. How does this affect 

 the sterilization of the water? It must be remembered that only 

 the very rapidly oxidizable organic substances can play any part 

 in diverting the oxygen from the living bacteria. If the oxygen is 

 not taken up by the organic matter in twenty or even ten minutes 

 it remains available during that period for the destruction of 

 B. c. c. or similar organisms, and, as they are attacked and de- 

 stroyed by it in this time, it follows that an excess of available 

 oxygen and chlorine demonstrable at the end of ten or twenty 

 minutes affords evidence that the " sterilization " of the water is 

 complete. If the whole of the oxygen and chlorine are absorbed 

 before the end of twenty minutes, and certainly if before the end 

 of ten minutes, it matters little whether it has been absorbed by 

 the bacteria or by the organic matter in solution — it has not 

 been allowed to act fully on the whole of the killable organisms, 

 and the more resistant remain capable of development and 

 multiplication, this applying not only to the B. c. c, but also 

 to the typhoid bacillus, the cholera vibrio and the bacillus of 

 dysentery, should any of these be present in the water being 

 treated. Now, gentlemen, you may say, what has all this to do 

 with the micro-biological problems arising out of the present war ? 

 My answer is : By Wright's method of inoculation patients are, 

 in a large measure, protected against the activities of the typhoid 

 bacillus, even though this bacillus gain access to the alimentary 

 canal. If, however, it is possible to cut off one of the sources 

 from which the typhoid bacillus may make its way into the 

 alimentary canal then we have provided an additional safeguard 

 against the disease, and have further diminished the possibilities 

 of typhoid infection and have also greatly diminished the 

 possibility of infection of cholera and bacillary dysentery, two 

 diseases against which at present little attempt can be made to 

 protect our troops by inoculation. We must act vigilantly and take 

 strict precautions to keep the water supplied to the troops pure, 

 especially in the hot months of the year, during which outbreaks 

 of most far-reaching and fatal character, the result of infection by 

 cholera vibrio and the dysentery bacillus, may make their 

 appearance. 



You may say, of course, that there is nothing new in all 



