are never transgressed in its natural motions. Everything takes place in souls as though there were no body, and in the body everything takes place as though there were no soul."
Lord Bacon accepted the doctrine of "vital spirits" as applied to both animate and inanimate bodies.
Glisson believed in "vital spirits intermediate between the soul and organs," and regarded "irritability as a force of which perception and appetite are factors."
Stahl, in the eighteenth century, enunciated the doctrine that chemical forces and vital force not only differ from each other, but are antagonistic. Chemical forces are destructive of the living body, and are held in abeyance, and their disintegrating power is neutralized by a vital force which resides in the body and ministers to its functions. "This vital force, struggling against physical force, acts intelligently, upon a definite plan, for the preservation of the organism"; its triumph secures life, while the rule of the physical forces alone brings death. The theories of "vitalism" and "animism" thus took their places among the philosophic ventures of the age.
Borden, Barthez, and Grimaud, "representing the school of Montpellier," accepted "vitalism" but rejected "animism." The principle of life was believed to be distinct from the soul, though it was thought to operate independently of mechanical or chemical laws.
Haller inaugurated the inductive method in physiological science, and, by experiments, located irritability in the muscular tissue and sensibility in the nervous tissue.
Buffon explained vital phenomena through the instrumentality of "organic molecules" which, differing in form and nature, were indestructible and endowed with the "properties of vitality." These molecules, when associated, not only gave specific character to each part of the organism, and provided for its physiological activity, but became the perennial source of life.
In order to explain how the organic molecules became arranged into the specific forms of life, and preserved individual and type identity in nutrition and reproduction, Buffon projected his theory of "interior molds," by which, in connection with the "organic molecules," he sought to account for all the phenomena of the organic world. It was not until 1827, when the ovule in the ovarian follicle of mammalians was discovered by De Baer, that the theory of "organic molecules" and "interior molds" was overthrown. A single demonstrated fact destroyed the speculations of an age.
Bonnet's theory of "included germs" was another example of reasoning from premises that had not been verified, and the result was disastrous to the subjective method. He taught that the germs of all life-forms not only pre-existed in their first-created representative, but actually contained within themselves, already formed, all the parts of the future organism.