Are there, then, any facts which the Darwinian theory of development by natural selection should explain and does not? Mr. Huxley himself says there is one set of such facts—the facts of hybridism; and, as we will presently see, there are a great many others. To St. George Mivart, a scientist, but more than a scientist, a philosopher in a degree, somewhat of a theologian as well, and therefore a man of greater intellectual grasp than either Darwin or Huxley, we are indebted for the fullest presentation of the facts inexplicable by natural selection that has yet been given to the reading world. This that gentleman has done in his book before referred to, _The Genesis of Species_. One of Mr. Mivart’s great merits is that he accords to Mr. Darwin’s theory its full meed of praise. He is a scientific man, and as such a good judge of its merits and demerits, therefore competent to acknowledge the one and point out the other. We are not at all prejudiced against Mr. Darwin or his theory. We agree entirely with Mr. Mivart that it “is perhaps the most interesting theory, in relation to natural science, which has been promulgated during the present century.” Before pointing out, however, why it is the most interesting theory of the kind, let us see in brief what the Darwinian theory of natural selection is. In the words of Mr. Mivart it may be stated thus: 1. “Every kind of animal and plant tends to increase in numbers in a geometrical proportion. 2. “Every kind of animal and plant transmits a general likeness with individual differences to its offspring. 3. “Every individual may present minute variations of any kind in any direction. 4. “Past time has been practically infinite. 5. “Every individual has to endure a very severe struggle for existence, owing to the tendency to geometrical increase of all kinds of animals and plants, while the total animal and vegetable population (man and his agency excepted) remains almost stationary. 6. “Thus, every variation of a kind tending to save the life of the individual possessing it, or to enable it more surely to propagate its kind, will in the long run be preserved, and will transmit its favorable peculiarity to some of its offspring, which peculiarity will thus become intensified till it reaches the maximum degree of utility. On the other hand, individuals presenting unfavorable peculiarities will be ruthlessly destroyed. The action of this law of ‘natural selection’ may thus be well represented by the convenient expression, ‘survival of the fittest.’” Now as to the series of facts which this theory throws light upon. Here they are as enumerated by Mr. Mivart. It explains: 1. Some singular facts “relating to the geographical distribution of animals and plants; as, for example, on the resemblance between the past and present inhabitants of different parts of the earth’s surface.