It is perfectly true that I have never heard of any Vailleton in biological science. Nor has anyone else. There is “no sich person.” Perhaps Mr. Belloc has not been able to read the manuscript of some adviser, or his memory may have played a trick upon him. Possibly he has in mind that eminent Victorian embryologist, Vialleton, who, so far from being the very newest thing in “European” biology, must now be getting on for seventy. He is half-way back to Haeckel, the originator of the family-tree idea, a German embryologist and not, as a matter of fact, the Victorian English Protestant Mr. Belloc supposes him to be. Possibly years and years ago some French student may have run away with the idea that embryos conscientiously repeat their phylogeny, and Professor Vialleton may have thought it well to discuss this idea in one of his books. It is not an idea I have ever entertained, much less stated, and its only interest here is that it gives Mr. Belloc a chance of showing how rudely he can set out his inaccuracies and his misconceptions. But this is an incidental comment. I will reserve for my next section a consideration of the remarkable arguments--“crushing arguments” the enthusiastic cross-heads of his editor declare them to be--that Mr. Belloc produces against this view of life as being in a state of change under the action of Natural Selection, that I have put here before the reader. III MR. BELLOC AS A SPECIMEN CRITIC OF NATURAL SELECTION The chief arguments against the Theory of Natural Selection with which Mr. Belloc has favoured us are neatly set out by him in two triads. His passion for orderly arrangement is greater than his logic, and we shall find that the second and third arguments of his second triad are substantially the same. He is rather exceptionally ignorant of modern scientific literature, and his arguments do not cover all the countervailing considerations upon which systematic observation and research work have been based--the speculations of Dr. Fairfield Osborn would have been a godsend for him--but the things he has to say are conveniently simple; they embody some prevalent misconceptions, and they will be useful in accentuating the more salient points in my account of the theory given in my second paper. He produces first certain remarkable _a priori_ arguments--his “three _a prior_ arguments.” The first is beautifully absurd. It is difficult to believe it is advanced in anything but a spirit of burlesque. He says that an advantage is not an advantage. He says that an advantage does not give an advantage unless it is combined with other advantages. You will think I am misrepresenting him. Then please read this:--