NATURAL THEOLOGY. 227 



when two laminae are pressed together, so that 

 these long fibres are forced far enough over the 

 short ones, their crooked parts fall into the cavity 

 made by the crooked parts of the others, just as 

 the latch that is fastened to a door enters into the 

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

 there hooking itself, fastens the door; for it is pro- 

 perly in this manner that one thread of a feather 

 is fastened to the other. 



This admirable structure of the feather, which 

 it is easy to see with the microscope, succeeds 

 perfectly for the use to which nature has designed 

 it, which use was, not only that the laminae might 

 be united, but that, when one thread or lamina 

 has been separated from another by some exter- 

 nal violence, it might be reclasped with sufficient 

 facility and expedition.* 



In the ostrich, this apparatus of crotchets and 

 fibres, of hooks and teeth, is wanting ; and we see 

 the consequence of the want. The filaments hang 

 loose and separate from one another, forming only 

 a kind of down, which constitution of the feathers, 

 however it may fit them for the flowing honours 

 of a lady's head-dress, may be reckoned an im- 

 perfection in the bird, inasmuch as wings composed 

 of these feathers, although they may greatly assist 

 it in running, do not serve for flight. 



* The above account is taken from Memoirs for a Natural His- 

 tory of Animals, by the Royal Academy of Paris, published in 

 1701, p. 219. 



