There is therefore strong evidence that antitoxin molecules do exist as part of the living substance of nerve cells.
A consideration of these facts emphasizes still more fully the view with which we set out, that all living substance is fundamentally, the same, though differentiated both anatomically and physiologically in many directions and in different degrees.
The growth of such a cell will be found to depend mainly upon five conditions: (I) There must be a supply of nutritive or plastic materials, at the expense of which the increase of its living substance can take place, and which supply the needed potential energy.
So long as food is supplied the living substance is the seat of transformations which are continually proceeding, being partially decomposed and again constructed, the new food being incorporated into it.
We see herein the reason for the great subdivision of the body, with its finely cut twigs and their ultimate expansions, the leaves, and we recognize that this subdivision is only an expression of the need to place the living substance in direct relationship with the environment.
There can be no doubt that there is no fundamental difference between the living substance of animals and plants, for many forms exist which cannot be referred with certainty to either kingdom.
The broad distinctions which, as a matter of fact, exist between every known form of living substance and every other component of the material world, justify the separation of the biological sciences from all others.
All living substance so far as is known at present (see Biogenesis) arises only from already existing living substance.
The way in which such food when manufactured is incorporated into, and enabled to build up, the living substance is again hidden in obscurity.
Living matter is a mixture of substances chiefly dissolved in water; the comparison with the crystals has led to a supposed distinction in the mode of growth, crystals growing by the superficial apposition of new particles and living substance by intussusception.