8. According not only to the common, but to the latest, opinion of physiologists, the germ supplies something more than " a direct- ing agency " (which must itself be a force). It not only directs, but it effects, or produces changes. It is an operative force, acting not by, but against physical foi-ces or chemical affinities ; counter- acting them as long as it continues. As soon as the germ or plant or tissue dies, the physical forces obtain ascendency and disintegra- tion takes place. This Dr. Carpenter himself admits. The most marked characteristic, he says, which distinguishes " vital fi-om every kind of physical activity," is, "the fact that a germ endowed with life, develops itself into an organism of a type resembling that of its parent ; that this organism is the subject of incessant changes, which all tend, in the first place, to the evolution of its typical form ; and subsequently to its maintenance in that form, noUvithstanding the antagonism of chemical and physical agencies^ which are continually tending to produce its disintegration ; but that, as its term of existence is prolonged, its conservative power declines so as to become less and less able to resist these disinte- grating forces, to which it finally succumbs, leaving the organism to be resolved by their agency into the components from which its materials were originally drawn." ^ This does not mean that chemical agencies have no part to act in the growth and develop- ment of plants and animals, but it certainly does mean that the vital force or life is an agency or power different from any kind of physical force. Life and physical force, therefore, are not iden- tical. They are not coiTclated. The former is not a mere form of the latter.
One of the most eminent of living physiologists is Dr. John Mai'- shall, and he, although far from belonging to the old school, dis- tinctly takes the ground that there is a vital force Avhich cannot be resolved into any of the physical forces operative in the external, inorganic world. He says r^ "All the strictly jihysical processes within the body, whether chemical, mechanical, thermic, electric, or photic, are performed by modifications of the common force which produces similar phenomena in the inorganic world around us. There exists, however, in the living animal, as in the living vegetable organism, a special formative or organizing energy, evolving the perfect animal or plant from the primitive ovum or ovule, developing its various tissues and organs, and conserving them from the commencement to the termination of its individual
1 Toumans, p. 407.
2 Outlines of Physiology, Smith's Philadelphia edition, 1868, p. 932.