12 



EVENINGS AT THE MICROSCOPE. 



elegant ; and this structure is continued to the very ex- 

 tremity, 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 



i W s "jL II accident; for in these dozen hairs there 



V"'-K are several in which we see one or more 



H/ 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 witli 

 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 oppc site. 



But more than the success of a schoolboy's magic de- 

 pends on the imbricate surface of hairs. England's time- 

 honoured manufacture, that which affords the highest 



HAIR OF INDIAN BAT. 



