INTERRELATION OF THE CHEMICAL SENSES 173 



discovery of food as well as in its appropriation, and 

 partake, therefore, more or less of the nature of extero- 

 ceptors. Although olf action has a function independent 

 and separate from that of gustation in scenting mates 

 or enemies and gustation has a function independent of 

 olf action initiates the feeding reflexes both muscular and 

 noxious material, both senses are intimately associated 

 in feeding. Food is found and the digestive secretions 

 are started through smell; it is swallowed and these se- 

 cretions are intensified ordinarily through taste. Thus 

 olfaction initiates the feeding reflexes both muscular and 

 secretory and gustation reinforces and completes them. 

 It is remarkable that in some fishes like the catfishes 

 (Amiurus) and especially the dogfishes (Mustelus; 

 Parker, 1914) feeding scarcely ever occurs, even when the 

 fishes are starving and food is present, unless the process 

 is initiated through olfactory reflexes. These seem to 

 be essential for that chain of events that result in the 

 final swallowing of the food, a condition that shows how 

 intimately smell and taste are interwoven in the verte- 

 brate organization. 



Smell and taste, though thus most closely involved in 

 the feeding reflexes, are nevertheless perfectly distinct. 

 As long ago as 1821 Cloquet (Larguier des Bancels, 1912) 

 showed that on closing the nose by pinching the nostrils 

 smell can be eliminated and only taste remains. Under 

 such circumstances it is surprising to those who have 

 not previously tried the experiment to discover how small 

 a proportion of our food sensations are due to taste and 

 how large a one to smell. A cold in the head commonly 

 eliminates smell and leaves taste. It reduces a person 

 to a state in which food is often described as without 



