Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: Dr. Macbride's narrative; he says that" some if not all the species of the genus appear to possess a kind of glandular function," without mentioning those that have it, or the absence of it in the only species growing around him at the north; and he adds that he " was entirely unacquainted with this curious economy . . . when I published the first edition of my ' Elements of Botany,' and even when I printed the appendix (in vol. i.) to the second edition of this work." Now his paper is dated September 11, 1811; and the volume referred to, as just printed, is dated 1812. But Macbride states that his observations were chiefly made 1810 and 1811; he corresponded intimately with Eliott, through whom, if not directly, his observations would probably find their way at once to the Philadelphia naturalists. NAUDIN ON THE NATURE OF HEREDITY AND VARIABILITY IN PLANTS.1 Why is it the nature and essence of species to breed true, and why do species sometimes vary ? In other words, why is offspring like parent, and when unlike in certain particulars, what is the cause and origin of the difference? We commonly and properly enough take these two associated yet opposed facts as first principles. But it is equally proper and legitimate to enquire after the cause of them. M. Naudin, a good many years ago, took up the study of hybrid plants, and followed up for a series of generations, the course of life of certain self-fertile ones, notably of Datura. "We gave at the time an abstract of his observations of the manner in which the characters of two closely related common species, D. Stramonium and D. Tatula, were mixed, and in which the characters of the two began to separate in the close- bred progeny of the next generation, ending in a complete division of the amalgamated forms into those ...