LESSON 27.] 



HAIK. 



85 



to be exquisite, and in proportion as the point, or other part nearer 

 the bulb be touched, the animal knows exactly whether it can pass 

 or not. 



447. For experiment sake, a cat has had her Vibrissse cut, and 

 then put into a box provided with a large round hole larger than 

 necessary for her body to pass through. But she has lost her gauge, 

 and no temptation can induce her to attempt to come out of the box. 

 Lions and tigers, following their prey in the jungle, are solely guided 

 by the refined sensibility of these organs, which (as already observed) 

 bleed when pulled out. 



448. The true structure of hair can only be known by examining 

 transverse sections of it, which require to be cut sufficiently thin, or 

 they are useless. 



449. Sections of the vibrissa of the Hat (Fig. 133), and of the 

 Raccoon (Fig. 134), show the same tissues as those described in man ; 

 the air which separates the cells in the medullary canal in human 



FIG. 133. Fio. 134 



Transverse section of vibrissa, Kat. Transverse section of vibrissa, Eaccoon. 



hair, is equally found exerting the like division in these hairs. Like 

 the vibrissse of the Tiger and the Cat, those of the Rat and Raccoon 

 are remarkable for the general roundness of their figure. There can 

 be no doubt that these organs are as important to the two last 

 mentioned animals, as to the former ; in the first, they tend to 

 ensure the capture of living prey in the last, they facilitate 

 escape. 



450. Hitherto, only one medullary canal has been described, as 

 being excavated (as it were) out of the cortical substance ; but in 

 the Pachydermatous (thick skinned) animals, to which the Elephant, 

 Hog, Horse, Rhinoceros, &c., belong, there are several medullary 

 canals apparent. 



A thin transverse section of a hair from the proboscis of the 

 Elephant (Fig. 135), is almost identical with a similar section of a 

 Hog's bristle (Fig. 136), and in both, a plurality of medullas appear 



