It is clear that you have not yet sufficiently read the book to enable you to criticise it.  It is a book in which every page and almost every line has a bearing on the main argument, and it is very difficult to bear in mind such a variety of facts, arguments and indications as are brought forward.  It was only on the fifth perusal that I fully appreciated the whole strength of the work, and as I had been long before familiar with the same subjects I cannot but think that persons less familiar with them cannot have any clear idea of the accumulated argument by a single perusal.

Your objections, so far as I can see anything definite in them, are so fully and clearly anticipated and answered in the book itself that it is perfectly useless my saying anything about them.  It seems to me, however, as clear as daylight that the principle of Natural Selection must act in nature.  It is almost as necessary a truth as any of mathematics.  Next, the effects produced by this action cannot be limited. It cannot be shown that there is any limit to them in nature.  Again, the millions of facts in the numerical relations of organic beings, their geographical distribution, their relations of affinity, the modification of their parts and organs, the phenomena of intercrossing, embryology and morphology—­all are in accordance with his theory, and almost all are necessary results from it; while on the other theory they are all isolated facts having no connection with each other and as utterly inexplicable and confusing as fossils are on the theory that they are special creations and are not the remains of animals that have once lived.  It is the vast chaos of facts, which are explicable and fall into beautiful order on the one theory, which are inexplicable and remain a chaos on the other, which I think must ultimately force Darwin’s views on any and every reflecting mind.  Isolated difficulties and objections are nothing against this vast cumulative argument.  The human mind cannot go on for ever accumulating facts which remain unconnected and without any mutual bearing and bound together by no law.  The evidence for the production of the organic world by the simple laws of inheritance is exactly of the same nature as that for the production of the present surface of the earth—­hills and valleys, plains, rocks, strata, volcanoes, and all their fossil remains—­by the slow and natural action of natural causes now in operation.  The mind that will ultimately reject Darwin must (to be consistent) reject Lyell also.  The same arguments of apparent stability which are thought to disprove that organic species can change will also disprove any change in the inorganic world, and you must believe with your forefathers that each hill and each river, each inland lake and continent, were created as they stand, with their various strata and their various fossils—­all appearances and arguments to the contrary notwithstanding.  I can only recommend you to read again Darwin’s