These are two lectures recently delivered before the Yale Theological School, and now issued in book form. Our interest in the work from a horticultural point of view is chiefly derived from a statement made in a recent lecture by the Rev. Joseph Cook, given in Boston on - so the authorized version says: - "February 30th," - a day, which, by the way, rarely occurs in other parts of the world. Dr. Cook says: "There are essential parts of Darwinism which are being silently modified or abandoned. Virchow, of Berlin; Allman, of the British Association; Dana, of New Haven: Wallace, of England: and Gray, of Harvard University, have all criticised Darwin in such a way that the right hand of that system of thought, or the doctrine that natural selection is an adequate cause of the origin of species is now a very limp and lame, I had almost said wholly severed member." As quotations are made from these lectures of Dr. Gray, we were anxious to see how Dr. Gray was silently modifying or mutilating his well known Darwinism. We have read the work carefully through, but have been unable to find what Mr. Cook found; and we are rather inclined to believe it is Mr. Cook that is silently finding that he never had any thing serious to fight, than that Dr. Gray has abandoned the contest.

In the first place it must be remembered that Mr. Darwin has never ventured to propose any theory of life. He finds life in the world in various forms, and he finds these forms possess an innate tendency to vary. He conceives this tendency to be influenced by good to the individual, and therefore that the. variations will be likely to follow those conditions most favorable to individual development. Now, the great question is, how do those assemblages of individuals which we know as species originate? There are groups of plants comprising individuals, so nearly like each other, that even a child would say they were " all of one sort, only a little different." The botanist groups these together. As soon as he finds some not quite like the others in essential particulars he stops. Sometimes he finds scores of these close resemblances, - sometimes only a few, - but there is generally a line where he feels he may stop. He calls them species. There is nothing certain or definite about the dividing lines.

At one time he finds the species grouped together go on in regular order, as 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12. At other times there are breaks in the apparent close connection, as 1,2, 4, 6, 8, 9, 10, 12. What is more natural than to suppose that close relationships were once the rule, and that the regularity has been broken up by unfavorable circumstances? In looking into nature, Mr. Darwin found that this is actually the case. There is a continual struggle for life, and only those most fit to contend with the circumstances survive. It is only the diversity that makes what man calls species. It is this dropping out of an occasional connecting link that makes the diversity, - in other words, that makes species, - and to show how this dropping out occurs under a continual innate power of varying, is the theory of Mr. Darwin, under the name of " natural selection." Some objection has been made to the theory that natural selection might vary, but not create form: but this objection could not come from a morphologist who has not yet been able to go to the bottom of form. New forms in the individual plants are known to grow out others. The seed vessel grew out of leaves.

It can be no worse in any law bearing on the origin of species.

Once in a while, as new facts appear, investigators like Gray, Darwin, and others, will naturally make suggestions, or advance hypotheses which may not accord with their own generalizations. To use a common, but not very elegant phrase, they for the moment " slop over." We believe this has often been the case in the discussion of incidental matters which the undoubted truths of Darwinism have led the world to examine. The writer of this has now and then found himself in antagonism to other students of nature in these side issues. But it will not be fair on this account to say of such issues that they evidence an abandonment of Darwinism, and we are quite sure no one who reads this little book without prejudice will believe that Dr. Gray is one bit less a Darwinian than he ever was.