Birds of British Columbia and Washington

Correspo•tde•tce.[-Auk [Oct.guess-work, with no basis in experiment, microscopical study, chemical analysis, or properly observed flints of any sort, as shown by Mr. Keeler's own statements.He is speaking, or supposes lie is speaking, of pig~ ment, but his remarks show that be refers to color in a broad sense.Yet no blue pigmeut has ever beea discovered, and green and yellow are well-known to be not by any means always due to pigment, bat are merely 'objective structural colors.'Thus, according to Gadow, violet and blue always belong to this category, green ahnost always, and yellow occasionally.And among the instances lie cites where "yellow l•athers are in reality without pigment" are snells.birds as Zeter•zs (!), •V•tJtt/tomelas, Picus, etc. Green, except in the Musopbagid•e, "is always due to yellow, orange, or grayish brown pigment with a special superstructure, which consists either of narrow longitudinal ridges, . . .or else . . . the sotface of the rami and radii is smooth and qnite transparent, while between it and the pigment exists a layer of small polygot•al bodies, similar to those of blue feathers."Further space cannot be given to the subject in this connection, but the reader is advised to carefully study, in connection with Mi'.Keeler's "theory of the assortment of pigments," and related parts of his work, the article on 'Colour' byDr.Hans Gadow in Professor Newton's recently pnblished'Dictionary or' Birds,' from which some of the above statements are quoted.It is evident that if Mr. Keeler had possessed what may be termed even a fair superlicial kno•vledge of the investigations that have been made respecting pigments, and the structure of I•athers in rehttion to color, lie conld not have propounded so utterly defenceless n hypothesis as his "Law of the Assortment of Pigments," and would have omitted a great deal of the "rul)bisb" that he has put into his book on the general satlject of the "evolution of colors" in birds.Many or'the minor points in Mr. Keelefts rejoinder are passed over as hardly de•nanding space for tbrmal consideration, even though the real bearing of my criticisms is iu several instances greatly misrepresented.In conclusion I may add that tbe task of reviewing Mr. Keeler's book was a painful one, and was prompted only by a sense of duty, not only to the many inexperienced readers who might be misled by it, but as a needed protest agalnsta very prevalent kind of psemto-science that has or'late gained great currency and popularity.That some such antidote was not wholly unnecessary is shown by the fact that the editor of a prominent scientific jonrnal is forrod to have endorsed one of its most groundless hypotheses.--J. A. ALLEN.]Birds of British Columbia and Washington.

Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.