EDITOR'S introduction. 



it is plain that by some mechanical means or other they catch or clasp among themselves, thereby 

 giving to the web its closeness and compactness of texture. Nor is this all. When two lamina? which 

 have been separated by accident or design are brought together 

 again, they immediately reclasp ; the connection, whatever it 

 was, is perfectly restored, and the web of the feather becomes 

 as smooth and firm as if nothing had happened to it. Draw 

 your finger down the feather, which is, so to speak, against 

 the grain, and you will probably destroy the junction between 

 some of the contiguous lamina? ; draw your finger up the 

 feather in the opposite direction, and you restore all to their 

 former state of coherence. This is no common contrivance. 

 Let us now inquire concerning the mechanism whereby it is 

 effected. The lamina? above mentioned, examined indi- 

 vidually, are found to be provided with vast numbers of long 

 fibres, or teeth, which project from their edges in such a 

 manner that, when placed in contact, those of contiguous 

 lamina? hook and grapple together. The fibres are extremely 

 minute ; indeed, fifty of them have been counted by means of 

 the microscope in the space of the J^th of an inch. Every 

 fibre is crooked, but bent after a definite manner ; those that 

 proceed from one edge of a lamina are long, flexible, and 

 bent downwards, whereas those that proceed from the oppo- 

 site edge are shorter, firmer, and turned upwards. The 

 manner in which they are united is, therefore, as follows : 

 When two contiguous lamina? are pressed together, so that 

 the long fibres are forced far enough over the short ones, 

 their crooked parts fall into the angles formed by the crooked 

 parts of the others, just as the latch of a door falls into the 

 cavity of the catch fixed to the door-post, and there hooking 

 itself, fastens the door. This admirable structure, which may 

 be readily seen with a very ordinary microscope, ensures not 

 only the union of the laminae, but renders it possible that 

 when any two of them have been separated by violence 

 they will become re-connected with facility and expedition. 

 In the ostrich, this apparatus of crotchets and fibres, of hooks 

 and eyes, is wanting ; the filamentary lamina? hang loose and 

 separate, forming a kind of down ; but such a plan of con- 

 struction, however it may fit the plumes for the flowing 

 honours of a lady's head-dress, must be considered as 

 detrimental to the bird, inasmuch as wings composed of 

 such feathers, although they may assist in running, will not 

 serve for flight. 



The power of inflating their whole body with air, and the possession of feathers, are therefore the 

 most distinctive endowments of a bird, inasmuch as these attributes are quite peculiar to the class. 



To creatures thus gifted with strength and activity so extraordinary, it is manifest that percep- 

 tions of great acuteness are requisite, corresponding with the rapidity of their movements and the 



Fig. 3. — NASCENT FEATHER OF A CHICKEN. 



c, the External Horny Sheath, slit open : d, d, Web 

 of the Feather produced in successive layers from 

 the central stem, e. 



