272 SENSATION AND THE SENSIFEEOUS OEGANS. 



alike against the poison of superstition and the counter- 

 poison of nihilism; by showing that the .affirmations of 

 the former and the denials of the latter alike deal with 

 matters about which, for lack of evidence, nothing can 

 be either affirmed or denied. 



I have dwelt at length upon the nature and origin 

 of our sensations of smell, on account of the compara- 

 tive freedom of the olfactory sense from the complica- 

 tions which are met with in most of the other senses. 



Sensations of taste, however, are generated in almost 

 as simple a fashion as those of smell. In this case, the 

 sense organ is the epithelium which covers the tongue 

 and the palate : and which sometimes, becoming modi- 

 fied, gives rise to peculiar organs termed "gustatory 

 bulbs," in which the epithelial cells elongate and as- 

 sume a somewhat rod-like form. Nerve fibres connect 

 the sensory organ with the sensorium, and tastes or fla- 

 vours are states of consciousness caused by the change 

 of molecular state of the latter. In the case of the sense 

 of touch there is often no sense organ distinct from the 

 general epidermis. But many fishes and amphibia ex- 

 hibit local modifications of the epidermic cells which are 

 sometimes extraordinarily like the gustatory bulbs ; more 

 commonly, both in lower and higher animals, the effect 

 of the contact of external bodies is intensified by the 

 development of hair-like filaments, or of true hairs, the 

 bases of which are in immediate relation with the ends 

 of the sensory nerves. Every one must have noticed the 



