10 STELLA BURNHAM VINCENT 



dark passages, are furnished with whiskers. The bat is sup- 

 posed to avoid walls and houses by the exquisite sensibility of 

 its wings: it seems, how^ever, probable that it is indebted for 

 its safety in this respect to its whiskers, or feelers as they may 

 be termed."^ 



The anatomists have, as a rule, been more interested in these 

 organs than the physiologists or psychologists and they usually 

 have something to say as to function. 



Odenius, who studied these hairs in 1866, thought that their 

 great innervation had to do with nocturnal habits, their superior 

 nerve supply making them peculiarly sensitive and useful in 

 determining the nearness of objects or the size of openings. •* 



Bonnet, in 1878, made a most exhaustive study of the inner- 

 vation of the follicle of the tactile hair and says in conclusion : — 

 " For the present one may only assume with certainty a quan- 

 titative difference in the power of touch based upon the greater 

 or less degree of innervation," and that " Only experiments 

 with living animals can give more certain results." He also calls 

 attention to the fact that the term touch, as ordinarily used, 

 includes the perception of two points, temperature, hardness, 

 etc., and proposes to abandon this name for the hair, which pro- 

 bably serves none of these, and regard it simply as a feeling hair 

 which gives spatial relations in the near as vision gives the far.^ 



One might cite other authors and other experiments but they 

 all follow the same general lines and we will pass at once to 

 some more recent work, and on the experimental side more 

 carefully controlled. 



Small studied the development of the young white rat and 

 some of his notes are as follows : — 



First day : ' ' Gave little response to light pressure as with a 

 hair except upon the nose which seems to be very sensitive." 



Seventh day: " Dermal sensibility becomes more acute, though 

 susceptibility to pressure is still greater on the nose than any- 

 where else on the body. Especially greater when tickling is 

 involved. A bristle drawn across the body elicits scarcely any 



^ Broughton, S. D.: On the Use of Whiskers in Feline and Other Animals. Lon- 

 don Medical and Physical Jour. 1823, vol. 49. 



* Odenius, M. V.: Beitrag zur Kenntniss des Anat. Baues der Tasthaare, Deutsch. 

 Archiv /. mikro. Anat. 11, S. 436. 



5 Bonnet, R.: Studien iiber der Innervation der Haarebalge der Hausthiere. 

 Morph. Jahrb. 1878 Bd. 4, S 361. 



