brief reference here made, but the perusal of it will certainly impress one with the profound change which has taken place in the method of treating a subject of this nature compared to the treatment it might have received in pre-Darwinian days. Indeed, the features discussed in this paper would not have attracted a moment's attention from the older naturalists.
Since Darwin published his provisional theory of Pangenesis it has provoked speculative efforts on the part of some of our naturalists to devise other hypotheses which might answer some of the objections urged against Darwin's hypothesis. Space will permit only a mention of a few of these papers. Professor W. K. Brooks[1] presented, in brief abstract, at the Buffalo meeting eleven years ago, a provisional theory of Pangenesis. These views, more elaborated, are now published in book-form, under the title of "The Laws of Heredity." An illustrious reviewer says it is the most important contribution on the speculative side of Darwinism that has ever appeared in this country. He has also aptly termed studies of this nature molecular biology. Dr. Louis Elsberg at the same meeting also read a paper on the plastidule hypothesis.
Dr. John A. Ryder[2] has made an interesting contribution entitled "The Gemmule versus the Plastidule as the Ultimate Physical Unit of Living Matter." In this paper he discusses Darwin's provisional theory of Pangenesis, and shows it to be untenable from Galton's experiments.
Haeckel's provisional hypothesis of the perigenesis of the plastidule is clearly stated, and he closes by saying that the logical consequences of the acceptance of Haeckel's theory, and with it the theory of dynamical differentiation—because the latter is no longer an hypothesis—forever relegate teleological doctrines to the category of extinct ideas.
The wide-spread public interest in Darwinism arose from the fact that every theory and every fact advanced in proof of the derivative origin of species applied with equal force to the origin of man as one of the species. The public interest has been continually excited by the consistent energy with which the Church—Catholic and Protestant alike—has inveighed against the dangerous teachings of Darwin. Judging by centuries of experience, as attested by unimpeachable historical records, it is safe enough for an intelligent man, even if he knows nothing about the facts, to accept promptly as truth any generalization of science which the Church declares to be false, and conversely to repudiate with equal promptness as false any interpretation of the behavior of the universe which the Church adjudges to be true. In proof of this sweeping statement, one has only to read the impos-
