Note 234 — RESEARCH IV.
Reading edition
Supposing the increase or diminution of living action when produced by different agents, uniform, similar and differing only in degree; it would follow, that certain mixtures of hydrocarbonate and nitrous oxide, or hydrogene and nitrous oxide, ought to be capable of supporting the life of animals for a much longer time than pure nitrous oxide. From the experiments in Res. III. Div. I. it appears however, that this is not the case.
It would seem, that in life, a variety of different corpuscular changes are capable of producing phænomena apparently similar; so that in the science of living action, we are incapable of reasoning concerning causes from effects.