8 Sir Everard Home on the conversion of Pus 
recommended its mixture with pus as the best criterion by 
which pus might be detected and distinguished from other 
animal fluids,) I now determined to try what effect it would 
have with respect to the appearance of the granulations; 
for although in some respects it is not a fair trial, since the 
chemical combination of pus with this solution might destroy 
the natural properties of pus, and convert it into a com- 
pound of a very different kind, still that was by no means 
necessarily the case. 
Upon pouring a saturated solution of sal ammoniac at the 
temperature of 45 0 upon the surface of a sore, the pus almost 
immediately became curdled, and tortuous canals were every 
where seen in these masses of coagulum. There was great 
uniformity in the tortuous canals; they were of the same 
size, running first in a straight direction, terminating in a 
spiral turn and a half, the end of which was extremely small ; 
they were all filled with red blood. It was remarked that, 
although the canals themselves were in greater number, there 
were fewer bubbles of gas than when the cold water had been 
used, more having been retained in the tubes. Some of the 
coagula of pus were more elevated than the general surface, 
and large canals filled with red blood were seen superficially 
passing over some of them, without any smaller ones in the 
immediate neighbourhood. To ascertain whether there was 
any vascular basis with which these canals were connected, 
I passed a tolerably large crooked needle under one of 
them, bringing out the point on the opposite side, so that 
the canal was distinctly seen above the flat surface of the 
needle : I then withdrew it, and there was not the slightest 
degree of extravasation of blood. This was repeated on 
