STRUCTURE OF SENSIFEROUS ORGANS 3H 



renders its possessor proof alike against the poison 

 of superstition and the counter-poison of shallow 

 negation; 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 

 comparative freedom of the olfactory sense from 

 the complications 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 modified, gives rise to 

 peculiar organs termed " gustatory bulbs," in 

 which the epithelial cells elongate and assume a 

 somewhat rodlike form. Nerve fibres connect the 

 sensory organ with the sensorium, and tastes or 

 flavours 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 exhibit local modifications of 

 the epidermic cells which are, sometimes, extraor- 

 dinarily like the gustatory bulbs; more com- 

 monly, both in lower and higher animals, the 

 effect of the contact of external bodies is intensi- 



