PUTREFACTION IN BLOOD. 59 



and even those who were constantly present were not quite 

 insensible to the evil. In operating with them the odour 

 was intolerable to me, and I was frequently obliged to leave 

 at an important moment for a breath of fresh air, whilst the 

 nausea was prolonged nearly to vomiting. My assistant 

 did not feel much annoyed, or I would not have asked 

 him to continue the work. On his leaving me, I was not 

 inclined to continue, at least without a considerable in- 

 terval of pleasanter work ; and this I found in a branch of 

 the subject relating to the absorption of gases. 



I mentioned that by passing the gas through lead and 

 other metallic salts, only a small amount of organic matter 

 was collected ; but by passing it through caustic potash 

 the amount was considerable. A flocculent matter fell, 

 but the chief amount remained in solution. The solution 

 was boiled down ; and when warmed, a perfectly fresh 

 odour of soup was spread through the room ; everything 

 offensive had been removed, and the smell was for the 

 first time very agreeable. Here we find that the sub- 

 stances sought for are decomposed by the very means 

 which we take to retain them. But in this experiment 

 we see a demonstration that substances of an organic na- 

 ture pass over with the gases. When strong sulphuric 

 acid was added to the potash solution, there was an 

 abundant black precipitate of carbon, showing that more 

 than enough for analysis had been prepared. There was a 

 fatty odour from it when sulphuric acid was added, lead- 

 ing me to think of some of Chevreul^s remarks on a similar 

 occasion. 



As these compounds were not retained by acid salts 

 but by alkalies, I concluded that they were acid. But 

 on allowing some of the solution to stand for a few 

 hours, I was surprised to find that the organic matter 

 had almost disappeared. This is the action of a neutral 

 body. 



