Page:Physiological Researches upon Life and Death.djvu/29

Rh part of physiological divisions offer only uncertain foundations to him who would raise upon them the edifice of science.

I shall not take notice of those divisions here; the best means of pointing out their insufficiency will be to prove the validity of the system which I have adopted. Let us now go over in detail the grand differences which separate the animal living from without, from the animal existing within itself in an alternate round of assimilation and excretion.

 

ARTICLE II.

GENERAL DIFFERENCES OF THE TWO LIVES WITH RESPECT TO THE EXTERNAL FORMS OF THEIR RESPECTIVE ORGANS.

most essential of the differences which distinguish the organs of animal life, from those of organic life, are the symmetry of the one, and the irregularity of the other. Some animals offer exceptions to this character, particularly as to animal life: such as among fish, soles, turbots, &c. different species of the non-vertebral animals, &c.&c. but it is exactly traced in man, as well as in those animals which approximate to him in perfection. In these only I shall examine it; to be satisfied of it a bare inspection is sufficient.

