"The ethical corollaries to Darwin's doctrine of the origin of species and to his theory of development through descent under the modifying influences of environment and natural selection have already passed these bounds of beneficence not only by demanding the mitigation of cruelty to slaves, but also by the abolition of slavery, and not only by inculcating the kind treatment of animals by individuals, but also by asserting the principle of animals' rights and the necessity of vindicating them by imposing judicial punishments for their violation."

“No one will seriously assert that the drosera, Dioncea muscipula, and other insectivorous and carnivorous plants are organisms superior in sensitiveness to those which they devour, or that this transformation of animal into vegetable structure increases the sum of pleasurable sensation m the world. The doctrine of evolution, which regards these antagonisms as mere episodes in the universal struggle for existence, has forever set aside this sort of theodicy and put an end to all teleological attempts to infer from the nature and operations of creation the moral character of the Creator.”

“Perhaps, with the introduction of more rational views of cosmogony and anthropology, and broader and more generous principles of psychology into our elementary text-books, through the union of a sounder physics with a larger metaphysics, our children's children may finally learn that there are inalienable animal as well as human rights, and that, in respect to the ties of moral obligation and the claims to kind and just treatment which they imply, not only "all nations of men," as Paul affirmed on Mar's Hill, but, as the Indian sage declared, "all living creatures are of one blood.”

“Do unto others as ye would that others should do unto you" is the golden rule; but far purer and more precious than gold is the injunction to do good without any reference to self, and to cultivate a morality that does not reflect the faintest tint, nor involve the slightest implication of self-love.”

“In the higher organisms the higher faculties predominate, and in the lower organisms the lower faculties: but in all of them, from the highest to the lowest, the action is the resultant of impulses of sensation, perception, conception, and thought variously combined and inextricably blended.”

“The recognition of an original affinity between man and beast, however remote the kinship may be, or whether it be based upon the ancient dogma of metempsychosis or the modern doctrine of evolution, necessarily creates a current of sympathy extending even to the most insignificant members of the great and widely diversified family of sentient beings, and rendering it impossible willfully to neglect or maltreat the "poor relations," to whom we are united by the warm and living ties of blood.”

“It is through the portal of spiritual kinship, erected by modern evolutional science, that beasts and birds enter into the temple of justice and enjoy the privilege of sanctuary against the wanton or unwitting cruelty hitherto authorized by the assumptions and usurpations of man.”