“ It is also necessary, he inferred, for all muscular movements, and he thought there was reason to believe that the sudden contraction of muscle is produced by its combination with other combustible (salino-sulphureous) particles in the body; hence the heart, being a muscle, ceases to beat when respiration is stopped. Animal heat also is due to the union of nitro-aerial particles, breathed in from the air, with the combustible particles in the blood, and is further formed by the combination of these two sets of particles in muscle during violent exertion. ”

“ Accepting as proved by Boyle’s experiments that air is necessary for combustion, he showed that fire is supported not by the air as a whole but by a “more active and subtle part of it.” This part he called spiritus igneo-aereus, or sometimes nitro-aereus ”