60 Proceedings of Royal Society of Ediribiirgh. [dec. 5 , 
small quantity of hot water ; then, if the water takes up the acid 
in the proportion of 20 to 1, by injecting 15 minims of the solu- 
tion before it is cold — say at the temperature of blood heat — I shall 
get into the system about f of a grain of the acid. Now, the 
medium dose by the mouth being 10 grains, \ of this would be 
reckoned safe, or at least not dangerous by injection, consequently 
I am much within the line of safety.” 
(4) Letter of Wtli March 1887. — “This forenoon I tried the 
injection of salicylic acid, and after injecting 5 or 6 minims into 
the tissue of the left thigh, I had to stop, owing to the pain caused 
by the acid. Judging by the pain that immediately followed the 
injecting of the drops of fluid, the solution must have been of 
considerable strength. The only question is, whether the heat of 
the body is sufficient to dissolve any crystals that remained in the 
fluid ? I suspect that this is the great fallacy of administering (say) 
10 grain doses of salicylic acid by the mouth. Possibly very little 
of the acid passes into the blood system, the greater part being 
carried away in the feeces as insoluble. From this, I am sure your 
method is on the right lines. The micro-organisms must he reached 
and must he destroy edi’ 
At this point Mr Snodgrass uses Dr Bergeon’s method along with 
the salicylic acid injections. 
(5) Letter of 2d>th March 1887. — “ Dr Bergeon’s instrument 
(the only one in Scotland) has been seen by my doctor. It is very 
elaborate ; we think needlessly so. Briefly, the mode of obtaining 
the mixed gas is to pass the carbonic acid gas through Eaux 
Bonnes water. Now, it seems that during five or six trials on a 
patient at the Western Infirmary (Glasgow) no sulphuretted hydro- 
gen could be detected being emitted through the mouth, showing 
that the gas did not permeate the lungs. My notion is that too 
little Eaux Bonnes water was used, that a fresh supply should from 
time to time have been put into the jar in which the CO 2 passed 
through the water. Your suggestion of the proportion of three 
volumes of CO 2 to 1 of H 2 S is very valuable.” 
Mr Snodgrass and his doctor construct a much simpler apparatus 
for this gaseous injection than that of Bergeon. 
(6) Letter of March 1887. — “At this point, I may say 
extensive damage has been done to the throat, for large ulcers are 
