AMERICAN CONTRIBUTIONS TO THE DEVELOPMENT THEORY.

Thames Star, Volume VII, Issue 2580, 14 April 1877, Page 4

AMERICAN CONTRIBUTIONS TO THE DEVELOPMENT THEORY.

(jBOM THE SCIENTIFIC AMEHIOAtf.)

The address which has deservedly attracted the greatest share attention, out of the many learned essays delivered at the recent meeting of the American Association for the Advancement of Science, is Professor E. L. Morse's masterly summing up of all that America has done to piomote the growth of the development theory. Professor Morse is an ardent evolutionist, a naturalist of great learning and ability, an iudefatigible investigator, and, like most prominent men in the scientific world, ha,s no hesitation in assuming the offensive in support of doctrines of the truth of which he is deeply convinced. Hence there is nothing resembling trimming in his discussion of the evolution question, the opponents of which receive scant mercy at his hands ; but still very many of these whose scientific faith is thus attacked are among the professor's warmest admirers, for he;possesses the happy faculty of being always instructive, always original, and of lilting his topics out of the slough of technical pedantry, in which too many of our learned scientists seem over inclined to bury modern acquisitions to a our knowledge, especially of natural history. Professor Morse tells us that the first clear premonition of the doctrine of natural selection came from an American, William Charles Wells, born at Charleston; South Carolina, 1757. In 1813 Wells read a paper before the Boyal Society, in which he attempted to account for the color, of dark-skinned races of men by citing the changes of animals under domestication, showing that varieties of men and animals were occurring,- not exceptionally, but constantly, and that different- breeds of animals were thus obtained by man's selective supervision. Hence he. argued that a similar selection among men had been effected by the comparative immunity from certain diseases of those who had dark skins. This is" substantially a part of the theory of natural selection now expanded by Darwin and credited wholly to him ; but the verdure of originality; it seems, mu3t now fade from the English naturalist's , laurels. The honour belongs to an American inventor, who like hundreds of his brethren since his day, has furnished the thoughts whence have sprung some of the most noted of foreign " discoveries." This is unquestionably the most important fact brought forward in Professor Morse's paper, and it will provoke universal comnient.

i Clapsifying the work of various' American investigators, Professor Morse tells us. that in jproducing new evidences for the doctrine of natural selection, Drs Burt G. Wilder,. Englemann, and W. K. Brooks and Professor Charles V. Riley have borne distinguished parts. Professor Riley's proof of the independence of flower and insect in the. case of the yucca moth is a scientific triumph. The late Professor Jefferies Wyman completely ruined the beautiful theory that the cells of bees were of. such construction as to use space and material to the best possible advantage. He found by close study that the cells of all cell-making insects are of all grades, from shapeless masses to those which approach but never reach perfection. The late Professor Chauney Wright also did admirable work in showing that the arrangement of leaves of plants along their axis was due to circumstances of growth, and was not a circumstance of blind law.

Professors S. F. Baird, J. A. Allen, and Robert Ridgway severally have found that marked difference in the birds and mammals are due solely to their surroundings. Thus, for example, western birds have ldpger tails than eastern ones of the same species, and on the Pacific coast birds acquir.e a darker hue. Large numbers of like changes, when tabulated and shown on a geographical chart, were found coincident with variations already ascer ; tamed in the amount of rainfall in the different regions. The total number of species of birds was reduced about onefifth by these investigations, and the number of squirrels decreased one-half more. As evidences of the transmutation of species, Mr James Lewis has discovered that a truncate form of mussel, which, by the loss of one of its segments, had been distinguished from another form, takes its peculiar shade from the circumstances to which it had been exposed, namely, the abrasion of its edges and consequent retarding of its growth in the rapid currents of the Mohawk River. Mr A. G. Wetherby has called attention to changes in snails under like conditions ; and Dr. Cooper and Messrs. Steams, Bland, an,d Birney.,.hate all described instances in which changes in animals have followed altered circumstances of heat or moisture. -,x Among the examples of the survival of forms by adaptation to changed environment, the discovery by Mr Ernest Ingersoll of marine molluscs and living salt water crabs high up on the rocky Mountains is the most remarkable. Professor Marsh has made a series of brilliant researches concerning tlie siredon, an animal of the salamander kind, that loses its gills and becomes, when removed from its natural habitat, one previously recorded under an entirely different genus (amblystoma). The researches of Drs. Papk&rd and Putnam :have overthrown Agassiz' theory that the blind fish of the Mammoth Gave are of a race created in their present by showing that a whole series of fishes, ranging from those with perfect eyes to those without any, including between them various deficiencies of vision, have been found in American caves and secluded waters. The discoveries of Professors Leidy, Marsh, and Cope among the tertiary mammals of the West, have filled wide gaps between older and existing forms, showing all the intermediate animals, so that we have nearly the whole ancestry of the horse, back to the fivetoed animal, not larger than a fox, in the eocene period. The remainder of Professor Morse's

admirable address sets forth the present theories of Darwin and the evolution school, and more especially dwells upon the gradual development of tho intellect of animals. The earliest mammals had the smallest brains; and as we go upward in the strata the siae of the brain gradually increases. Its development in the monkey tribe was regarded as the means by which these animals were enabled to escape from the Carnivora which formerly abounded; and intellect even in that early era thus proved its superiority to brute force.