Strychnin and adrenalin when injected into cardiectomized frogs are efficiently distributed all over the animal body and when administered in sufficient quantities produce the usual reactions of these alkaloids.
The experiments with strychnin prove positively that the paralysing effect of this poison is due to its direct action upon the nerve cells of the cord, and not, as Verworn assumes, to a paralysing action upon the heart.
When morphin is injected into cardiectomized frogs the effects are much greater and incomparably more rapid than when administered to a normal frog. The normal circulation probably contains substances derived from some organs capable of modifying and retarding the specific effects of morphin.
The distribution of solutions in animals deprived of their circulatory apparatus takes place through the tissue spaces, which present a more or less well connected system of communications throughout the entire animal body, especially through its peripheral parts. This mode of distribution is designated as the peripheral mechanism. In contrast to the centralizing cardiovascular apparatus, the peripheral mechanism permits a greater autonomous action of organs and a more localising effect of injections.
The peripheral mechanism found to be active in animals deprived of their circulation is probably identical with the mechanism which serves for distribution of the mesolymph in living animals not yet possessing a circulatory apparatus. The existence of the peripheral mechanism in animals with a cardiovascular apparatus possesses probably a phylogenetic significance.
It is assumed that the activity of the peripheral mechanism is probably not completely suppressed even in the presence of a normally acting circulatory apparatus; that it exerts a greater physiological influence in parts in which the circulation is normally some-what difficult; and that it unfolds an activity in pathological conditions in which the circulation has been eliminated or reduced in some parts of the body, or in which the energy of the entire circulation has been reduced.