1866.] Proceedings of the Asiatic Society. 229 



ashore was exposed to many sources of disease a great deal more 

 powerful than the waters of the Hooghly. 



Mr. Walclie gave explanations and replies to the several speakers, of 

 which the following were the principal ; — 



The principal difference between stagnant and running waters was, 

 that in the former the fermentative or putrefactive process tended to 

 be the prominent one, and yielded products which exercised a deoxy- 

 dating influence, and therefore required a greater quantity of oxygen 

 when tested by the permanganate. In running streams again the 

 process was more of an oxydating one, from the much larger amount 

 of surface exposed to the air. 



But the question at issue was, the amount of organic matter by 

 weight. He did not consider that the delay in examining some of 

 his samples could materially affect the correctness of his results, except 

 possibly in the case of the December and February waters, which had 

 stood over three or four months ; though even in these, judging from 

 observations he had made, there was not probably any great error. 

 But he would put these aside, as the point in question had reference 

 to the water of the hot season and of the rains. The formation of 

 vegetable growth in the bottles was very striking, and illustrative of 

 the excess of organic matter, in the earlier part of the rains more parti- 

 cularly, which very decidedly exceeded that in the water of the end 

 of the hot season. There was no great delay in examining the hot- 

 season water : that of 14th June, at the very end of the hot season, was 

 examined only nine days after collection, and gave only 1 T 4 ^ grains 

 organic matter per gallon, being the largest amount found in the 

 water of the hot-season. The water of the rainy season stood about 

 a month in the earlier samples, waiting till it settled, as the presence 

 of the finely divided clay, which could not be separated by filtration, 

 was a great difficulty in the way of estimating the organic matter, 

 i and though this could be removed easily, the processes required 

 made the subsequent determination of organic matter of doubtful 

 accuracy. 



He would not enter into the conclusions drawn from medical 

 statistics. His business at present was simply to state his results, 

 and leave it to the medical men to drawn conclusions from them. 

 His object was to supply correct data. 



