We have referred to William Swainson's advocacy of the "Circular" or "Quinarian" system of the classification of animals, with him amounting almost to a monomania, which was one of the most notorious examples of reasoning in a circle of which zoölogists have ever been guilty. It was a serious attempt to rationalize nature in a wholly irrational manner, and must be regarded as a curious by-product of minds fixed in the belief of a special creation,—to whom every form of evolutionary doctrine was sacrilegious and abhorrent. Its advocates, nevertheless, were sincere, and Swainson probably regarded himself as a martyr to the cause. As a later critic remarked, the system served him well by investing with a cloak of originality his treatises on those classes of animals with which he had little first-hand knowledge. His work on fishes is regarded as "a literary curiosity, the appearance of which was a misfortune to a man who, by his indefatigable industry under by no means favorable circumstances, had contributed as much as any of his contemporaries to the advancement of Zoölogy and its diffusion among the people."[109] This egregious doctrine, which its disciples called "the natural system" without grasping the true meaning of "affinity," or "homology," to use the more modern word, vitiated most of their writings; abler men played with it for a time, only to cast it aside, and no one but a historian or a psychologist would now give it a passing thought. So far as Swainson was concerned, Audubon's conduct appears to have been above reproach, and it must be regarded as fortunate that this ardent "Quinarian" did not have a hand in the _Biography of Birds_, for if it were really true that Audubon could have brought himself to accept the artificial system then in vogue, American ornithology, as Elliott Coues remarked, escaped a great affliction.