298 ANNUAL OF SCIENTIFIC DISCOVERY. 



further attention, renders this culture particularly-worthy of attention. 

 This worm has also recently been introduced into this country by Dr. 

 Stewardson,of Philadelphia, who, in a recent communication to the 

 Philadelphia Academy, states, that his experiments satisfy him, that 

 our climate is well adapted to raising it, and that in the latitude of the 

 Middle States, two crops of silk can be obtained in a season. Worms 

 placed upon ailanthus trees, in a private garden in Philadelphia, ex- 

 posed without care to all the mutations of the season, came to maturity 

 during the summer and spun their cocoons most perfectly. 



THE SENSES OF SMELL AND TASTE. 



The following is an abstract of an essay on the above subject by 

 Norton Folsom, Esq., for which a prize was awarded by the Boylston 

 (Mass.) Medical Society. 



These senses are so mingled in action that their separate offices are 

 at first difficult to determine ; and even the exact locality of the per- 

 ceptions which constitute the two senses can hardly be pointed out 

 without careful observation. We instinctively know that we smell 

 odoriferous substances when they are presented to the nose, and that 

 we taste sapid substances in the mouth, but more than this we can 

 only derive from experiment. 



When a substance to be tasted is placed in the mouth, we press it 

 with the upper surface of the tongue against the palate, and thus force 

 its particles in every direction, the saliva, poured in by its glands re- 

 sponsive to the stimulus, aids in dissolving and disseminating the par- 

 ticles over the mouth. When the substance reaches the fauces, and as 

 it is swallowed, a current of air escapes from the glottis, and carries 

 any volatile portion to the posterior nares, where it is liable to affect 

 the sense of smell. Plainly, therefore, in order to separate the two 

 sensations, we must either shut off the cavity of the nose during the 

 tasting, which can be done by most persons voluntarily, by breathing 

 through the mouth and applying the soft palate to the back of the 

 pharynx, or we must interrupt the current of air through the nares, 

 which can be done by holding the nose with the fingers. 



We recognize two classes of impressions made by articles of food, 

 one of savors, of which salt affords an example ; the other of flavors, 

 as that of vanilla. Most substances have both properties ; thus a straw- 

 berry has an acid and a sweet taste, besides its own delicious flavor. 



The distinction between these two classes has not, indeed, been fully 

 made by physiologists until of late ; and still less has the fact been rec- 

 ognized, that all flavors are perceived by the organ of smell only, re- 

 ducing the number of impressions which the organ of taste is capable 

 of receiving to four only, namely, sweet, sour, salt, and bitter. This 

 can, however, be easily and certainly demonstrated. Let the nose be 

 closed by the fingers, or let the posterior nares be shut off by the soft 

 palate, and a solution of vanilla be taken into the mouth and swallowed. 

 It cannot be distinguished from water. Soup, nutmeg, cheese, pine- 

 apple, and assafcetida are alike entirely flavorless under similar condi- 

 tions, though the ordinary sensibility of the mucous membrane, and 

 the perception of the four savors above mentioned, may enable us to 

 apprehend certain other qualities which distinguish these substances. 

 The common practice of holding a child's nose while it swallows disa- 



