It is perfectly true that obligations and duties are between moral persons, and therefore the lower animals are not susceptible of the moral obligations which we owe to one another; but we owe a seven-fold obligation to the Creator of those animals. Our obligation and moral duty is to Him who made them and if we wish to know the limit and the broad outline of our obligation, I say at once it is His nature and His perfections, and among these perfections one is, most profoundly, that of Eternal Mercy. And therefore, although a poor mule or a poor horse is not, indeed, a moral person, yet the Lord and Maker of the mule is the highest Lawgiver, and His nature is a law unto Himself. And in giving a dominion over His creatures to man, He gave it subject to the condition that it should be used in conformity to His perfections which is His own law, and therefore our law (The Zoophilist, London, 1 April, 1887).