ANIMALS AND PLANTS. 27 



forms of vegetable life, as, for instance, the anaerobic bacterium, Clostridium 

 pasteurianum, is capable of assimilating free nitrogen. 



At times plants also exhibit free kinetic energy such as it is customary to 

 encounter in the case of animals. Certain plants, as, for instance, the aroids and 

 others, develop considerable amounts of heat during the flowering-period. It is 

 also to be borne in mind that, in the development of the solid parts of plants, 

 the transformation of formative fluids into solid matter causes heat to be set free. 

 Absorption of oxygen and elimination of carbon dioxid have also been observed 

 in plants. These processes are, however, so insignificant as compared with those 

 described as typical in the vegetable kingdom, that they may be considered as 

 of little or no importance. 



Thus, plants are, on the whole, organisms that through the agency 

 of reduction-processes convert simple stable combinations into complex 

 ones, with the transformation of kinetic solar energy into the chemical 

 potential energy of vegetable matter. Animals are living organisms in 

 which through the agency of processes of oxidation the atom-groups 

 of complex construction furnished by plants are split up, the potential 

 energy being transformed into kinetic energy, which makes itself mani- 

 fest in the animal. Thus a circulation of materials and a constant 

 interchange of energy take place between animals and vegetables. All 

 of the energy of animals is derived from plants and all of the energy 

 of plants is derived from the sun. Therefore, the latter is the cause, 

 the ultimate source of all of the energy of organism, that is, of life as a 

 whole. As the generation of the sun's heat and light can be explained 

 by the gravitation of masses, so it is possible that the force of gravita- 

 tion is the sole ultimate form of energy for all living things. 



"The sun is the constantly bent spring that brings about the activity in the 

 atmosphere, that raises the waters to the clouds, that causes the tides. Light, the 

 most mobile of all forms of force, intercepted by the earth in flight, is transformed 

 by plants into a rigid state, for plants produce upon it a continuous sum of chem- 

 ical difference, constitute a reservoir in which the fugitive rays of the sun are 

 fixed and, adapted for useful purposes, are deposited. Plants take one form of 

 energy, light, and reproduce another, chemical difference. In the course of the 

 processes of life, but one transformation, both of matter, as well as of energy, takes 

 place, but never is the one or the other produced " (Julius Robert v. Mayer, 1845). 

 ("Omnia mutantur, nihil interit." Ovid.) 



The generation of kinetic energy in the animal body from the poten- 

 tial energy of the plant can be ma'de readily comprehensible by means 

 of a comparison. The atoms of the matter generated in organisms may 

 be conceived to be simple small bodies, spherules or blocks. So long as 

 these lie in a single layer or at least arranged in a few layers upon the 

 ground, a condition of rest and constancy will prevail in consequence of 

 this simple and stable arrangement. If, however, an artificially arranged 

 formation of unstable construction is built up from the small bodies, 

 there will be required (i) the motor force of the constructing agency, 

 which raises and combines the units. As soon, however, as (2) an 

 impulse from without acts upon the completed unstable structure, the 

 atoms collapse and the impact of their fall generates heat (eventually 

 also kinetic energy in the course of other complicated transformations), 

 that is, the energy applied by the constructing agency is transformed 

 into the form of energy last named. In plants the complicated unstable 

 construction of the atom-groups takes place, the sun being the con- 

 structing agency. In the animal body, wherein the plant is consumed, 

 the atomic structure is disintegrated into simpler elements, with the 

 generation of kinetic energy. 



