2 PTERYLOGRAPHY. 



We may, however, justly wonder that a subject so readily accessible, and furnishing such 

 beautiful results as the plumage of birds, has hitherto been so remarkably neglected by zoologists. 

 And yet feathers (to which with the other horny dermal appendages I should prefer to give the name 

 of skin-plants or dermatophytes [dermatophytd], inasmuch as they are all products of the skin which 

 take root therein after the manner of plants) are not only easy of investigation, but also extremely 

 agreeable subjects of examination, because they present a greater variety and multiplicity than can be 

 met with elsewhere within the same limits. All the allied structures, such as hairs, bristles, spines, 

 &c., are exceeded by feathers, not only in the number and variety of their constituent parts, inasmuch 

 as they generally possess no branches, and these, when present, are always simple, but also in the 

 complicated structure of these parts, and, consequently, of the whole. Feathers also exceed the 

 allied structures in their comparatively very large size, and in the part which they take in the 

 movements of birds, for the wings without the feathers would be useless for flight ; again, the 

 feathers both protect and warm the body, without greatly adding to its weight. Besides these 

 properties it must be mentioned also that birds are indebted chiefly, if not entirely, to their 

 feathery covering for the elegant and pleasing form which procures them so many friends and 

 admirers. It is certain that the greater part of that public which does not follow out scientific 

 objects in the study of zoology would detest birds if they were featherless animals, as much as 

 naked batrachians and lizards, which now excite almost universal aversion, however beautiful 

 they may be in their colours. Now, if even the masses are attracted by these properties of the 

 plumage of birds, how much more should the scientific observer be excited to the most industrious 

 investigation, when he perceives the almost innumerable differences which birds' feathers present 

 in every possible respect ; when besides the most multifarious form and structure he detects an 

 equally complicated arrangement and grouping upon definite regions of the body, and observes 

 these differences not merely in the numerous species, genera, and families, but also in different 

 ages and sexes of the same species, and even at different seasons of the year, on one and the same 

 individual. In all these and several other respects the feathers of birds will present him with 

 distinctions highly deserving of his notice. 



After hearing these assertions, the correctness of which is confirmed by the experience of 

 many years, my reader will share with me in the surprise expressed at starting, that so rich a 

 material for scientific labour can have remained so long unused. But it is still more astonishing 

 that, notwithstanding the great problem which it presents, this subject has been so superficially 

 touched upon by all the writers who have treated of it. For although statements with regard to 

 the feathers of birds are not entirely wanting, 1 and many good observations occur amongst those 

 which have been published, yet these investigations have been made less by ornithologists than by 



1 See especially HEUSINGER'S ' System der Histologie/ I, 2, 207, and, besides the writings of MAL- 

 PIGHI, HOOKE, LEEUWENHOEK, CAMPER, BASTER, POUPART, the two WENZELS, BLAINVILLE, AUDEBERT, 

 and others therein cited, the following works : CUVIER, ' Le9ons d'Anat. Comparative ;' TIEDEMANN'S 

 ' Zoologie,' II, 129 ; ALB. MECKEL, " liber die Federnbildung,'' in ' Reil's Archiv fur die Physiol.,' xii, 

 1 ; CARUS, ' Lebrbuch der Zootomie/ p. 441 ; DUTROCHET, " De la Structure et de la Regeneration des 

 Plumes," in the ' Journ. de Phys.,' Ixxxviii, p. 333 ; P\ CUVIER, "Obs. sur la Structure et le Developpe- 

 ment des Plumes," in the 'Mem. du Museum, 1826/ MACGILLIVHAY, in Jameson's 'Edinburgh New 

 Philosophical Journal,' III, p. 253; CARUS, ' Erlauterungstafeln zur vergleicli. Auat./ II, p. 11, taf. ii, 

 tigs. 1418 ; and also EBLE, ' Die Lehre vou den Haaren,' I, p. 128. 



