12 



EVENINGS AT THE MICROSCOPE. 



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elegant ; and this structure is continued to the very 

 extremity, which is not drawn out to so attenuated a point 

 as the hair of the Mouse, though it is of a needle-like 

 sharpness. The trumpet- shaped scales 

 are, it seems, liable to be removed by 

 accident ; for in these dozen hairs there 

 are several in which we see one or more 

 cups rubbed off, and in one the stem is 

 destitute of them for a considerable 

 space. The stem so denuded closely 

 resembles the basal part of a Mouse's 

 hair in its ordinary condition. 



This character of being clothed with 

 overlapping scales, each growing out of 

 its predecessor, is common, then, to the 

 hairs of the Mammalia, though it exists 

 in different degrees of development. It 

 may be readily detected by the unaided 

 sense, even when the eye, though as- 

 sisted by the microscope, fails to recog- 

 nise it. Almost every schoolboy is familiar with the mode 

 by which the tip of any hair may be distinguished from 

 its base ; and, even of the least fragment, the terminal end 

 from the basal end. A hair is rubbed to and fro between 

 the finger and thumb, and it regularly travels through in 

 the direction of its base ; thus enabling the boy after one 

 or two rubs to pronounce a very decided opinion on the 

 subject. Now you see the cause of this property lies in 

 the imbricate structure ; the scales may be ever so thin 

 and close, but still they project sufficiently in any speci- 

 men to present a barrier to motion in the direction of the 

 tip when pressed between two surfaces, such as the fingers, 

 while they very readily move in the opposite. 



But more than the success of a schoolboy's magic 

 depends on the imbricate surface of hairs. England's 

 time-honoured manufacture, that which affords the highest 



s ^ 



HAIR OF INDIAN BAT. 



