Charles Sedgwick Minot

The Study of Zoology in Germany

neighboring forests, and as the wild turkey has been driven back by the settlement of the country, the domestic turkey has gradually lost the markings which told of the presence of the wild, though j udicious breeding has preserved and rendered more or less constant some of this evidence in what is called the domestic bronze turkey; and the more these evidences are preserved in the bronze turkey, as the red leg and the tawny shade dashed upon the white terminals of the tail feathers and the tail coverts, the better should the stock be considered, because it is the more like its wild ancestor. That the domestic turkey in its neighborhood may be descended from or largely interbred with the wild turkey of New Mexico, which in its wild state more resembles the common domestic turkey than our wild turkey does, may unquestionably be true, and it may be also true that the wild turkey there has a large infusion of the tame blood, for it is well known that not only our domestic turkey, but even our barn-yard fowls relapse to the wild state in a single generation when they are reared in the woods and entirely away from the influence of man, gradually assuming uniform and constant colorings. But I will not discuss the question whether the Mexican wild turkey is of a different species from ours or merely a variety of the same species, only with differences in color which have arisen from accidental causes, and certainly I will not question that the Mexican turkey is the parent of many domestic turkeys, but I cannot resist the conclusion that our wild turkey is the progenitor of our domestic turkey. Indeed, we know that this is so to a very large extent, from their constant interbreeding along our frontiers, and I never heard of any one who had wild blood in his flock who did not think he had as good domestic turkeys as any one else.

On Heredity and Rejuvenation

The subject of this article is presented under the following sections: I. The Formative Force of Organisms. II. The Conception of Death. III. A Comparison of Larva and Embryo. IV. Concluding Remarks. The first section is not new, but a reproduction without change, of an article published in Science, July 3d, 1885. As this article has not become generally known, and yet is an essential link in the chain of reasoning, I venture to repeat itThough written in 1885, I consider that to-day it is still sufficient to disprove Weismanns theory of germ plasm. Weismann has not considered this article, otherwise, from my point-of view, he could not have maintained his theory.

A TRIBUTE TO JOSEPH LEIDY.

JOSEPH LEIDY was a son of the University of Pennsylvania. As a token of reverence and affection his devoted nephew and namesake, Joseph Leidy, Jr., has generously endowed the Joseph Leidy Memorial Lectureship for the extension of scientific knowledge through the medium of lectures by eminent specialists. To-night, we meet to inaugurate this foundation. Of Dr. Leidy, the great student and teacher, whom many of us knew and deeply honored, I would say:

The Study of Mammalian Embryology

THIS article is intended to give a preliminary account of a Tesr-book of Embiyology, upon the preparation of which I have been working for a considerable period. The book is intended especially to meet the needs of the student of human anatomy, but it is hoped to render it suitable for use as a general introduction to vertebrate embryology. The distinctive aim of the work will be to direct the beginner in the practical laboratory study of mammalian embryology, guiding him through an intelligent examination of the external form and of the microscopic sections. The publication of Foster and Balfours admirable Elemicuts of Embiy1ology gave a great impetus to the science, but it is, unfortunately, many years since the last edition of that work appeared (1883). Duvals Atlas is at present the most available guide, but is too elaborate and costly to be within the reach of most students. It is a work which ought to be in every laboratory, for it is a fine monument of well-directed learned industry. Both of these works deal with the embryology I Copyright, Ji900, by Charles Sedgwick Minot.

On Heredity and Rejuvenation (Continued)

It has long been known that animals develop according to two types, appearing in their younger stages, either as larvae or as embryos. The larvae lead a free life and must obtain their own food. Embryos, on the contrary, do not lead a free life and are nourished by the yolk accumulated in the parent ovum. There is, of course, no absolute demarcation between the two classes; nevertheless, a general comparison between them establishes several conclusions which throw valuable light upon some recent biological hypothesis. First of all, it must be remarked that the larval development is primitive, and that the embryonic development has been evolved later. Geologists are able to present two principal supports for this assertion: 1. In the lower animals we encounter only larvae, never embryos; sponges, colenterates, echinoderms and worms, all pass through the early stages of