When Darwin published the “Origin of Species,” he was aware that theologians and philosophers seemed to be fully satisfied with the view that each species had been independently created, and was immutable.  To his own mind, however, it accorded better with what was known of the laws impressed on matter by the Creator that the production and extinction of the past and present inhabitants of the world should have been due to secondary causes like those determining the birth and death of the individual.  “When I view,” he said, “all beings not as special creations, but as the lineal descendants of some few beings which lived long before the first bed of the Cambrian system was deposited, they seem to me to become ennobled.”  And again:  “As all the living forms of life are the lineal descendants of those which lived long before the Cambrian epoch, we may feel certain that the ordinary succession by generation has never once been broken, and that no cataclysm has desolated the whole world.  Hence we may look with some confidence to a secure future of great length.  And as natural selection works slowly by and for the good of each being, all corporeal and mental endowments will tend to progress towards perfection.”

For his own part, Darwin could see no good reason why the views propounded in the two volumes comprising the “Origin of Species” should shock the religious feelings of any one.  Touching the likelihood of such a result, he reassured himself by recalling the fact that the greatest discovery ever made by man—­namely, the law of the attraction of gravitation—­was attacked by Leibnitz “as subversive of natural, and inferentially, of revealed, religion.”  Darwin was confident that, if any such impressions were made by his theory, they would prove but transient, and that ultimately men would come to see that it is just as noble a conception of the Deity to believe that He created a few original forms capable of self-development into other and needful forms as to believe that it required the fresh act of creation to supply the voids caused by the action of His laws.

IV.

It was, as we have said, in 1868 that Darwin published the two volumes collectively entitled “Variation of Animals and Plants under Domestication.”  It is the second and largely corrected edition brought out in 1875 which we have under our eye.  It is the outcome of the views maintained by the author in this work and elsewhere that not only the various domestic races but the most distinct genera and orders within the same great class—­for instance, mammals, birds, reptiles, and fishes—­are all the descendants of one common progenitor, and the whole vast amount of difference between these forms has primarily arisen from simple variability.  Darwin recognized that he who for the first time should consider the subject under this point of view would be struck dumb with amazement.  He submits, however,