PHYSICAL AND CHEMICAL AGENTS UPON BLOOD. 
689 
In relating the experiments, I have sedulously avoided advancing any theories with 
regard to the mode of action of any of the agents studied, and on one or two occasions 
only has even as much as a hint been given that the results obtained might in any way 
tend to the elucidation of the action of remedies or the mode of death by poison. The 
reticence in this instance has arisen from the circumstance that several of the results are 
so novel and at the same time so pregnant with material for theorizing, that the indi- 
vidual facts might soon be lost sight of in a sea of speculation. It appears to me there- 
fore that the ends of science will be much better served if I confine myself to a descrip- 
tion of the bare data, rather than propound the numerous theories which the different 
results suggest, and which, although they might make the paper more interesting, could 
not in reality add to its true value. 
I may also mention that the material is so arranged as to be easily accessible, each 
fact having been made as far as possible independent of its associates, in order that 
future inquirers may find no difficulty in isolating any particular result they may desire 
specially to investigate. Moreover, the progressive details of each experiment are given 
in the form of an appendix, so that the initiated investigator can follow it with facility 
through its different stages, either for the purposes of comparison or verification *. 
Past I. — INFLUENCE OF PHYSICAL AGENTS. 
(a) The effect of Diffusion in modifying the composition of atmospheric air confined 
with fresh blood. 
The influence of both venous and arterial blood was studied. 
1st. As regards arterial blood. 
A certain quantity of arterial blood was allowed to flow directly from the femoral 
artery of a healthy dog into a glass receiver, and after being carefully secured along with 
100 per cent, of atmospheric air, was placed aside in a warm room during forty-eight 
hours. At the end of this time the receiver was opened in the manner already described, 
and a certain quantity of its gas removed for analysis. 
* The Appendix is deposited for reference in the Archives of the Loyal Society. The first analysis only is 
given in detail as a specimen. 
5 C 2 
