PHYSIOLOGY OF OLFACTION. 167 



by savoury smells upon the appetite. It is not probable, that absorp- 

 tion can occur to a sufficient extent to account for the apparent satia- 

 tion. The fact can only be explained by the effect upon the nervous 

 system, which influences the appetite materially, as we see in the effect 

 of various mental emotions. The first impact of a nauseous odour, or 

 even the view of a disgusting object, frequently converts the keenest 

 appetite into loathing. Yet, anciently, it was believed, that life might 

 be sustained for a time, by simply smelling nutritious substances. 

 Democritus is said to have lived three days on the vapour of hot 

 bread ; and Bacon refers to a man who supported an abstinence of 

 several days by inhaling the odour of a mixture of aromatic and alli- 

 aceous herbs. Two hundred years ago these notions were entertained 

 to a great extent; and they suggested the viaticum for travellers pro- 

 ceeding to the moon, according to the plan proposed by Dr. John Wil- 

 kins, Bishop of Chester. 1 "If we must needs feed upon something," 

 he remarks, "why may not smells nourish us?" Plutarch and Pliny, 

 and divers other ancients, tell us of a nation in India that lived only upon 

 pleasing odours ; and it is the common opinion of physicians that these 

 do strangely both strengthen and repair the spirits." Fuller, 2 a learned 

 cotemporary of the bishop, affords an amusing instance of litigation, 

 arising from this supposed nourishing character of odours. A poor 

 man being very hungry, stayed so long in a cook's shop who was dish- 

 ing up the meat, that his stomach was satisfied with the smell thereof. 

 The choleric cook demanded of him pay for his breakfast; the poor man 

 denied having had any; and the controversy was referred to the deci- 

 sion of the next man that should pass by, who chanced to be the most 

 notorious idiot in the whole city: he, on the relation of the matter, 

 determined that the poor man's money should be put betwixt two empty 

 dishes, and that the cook should be recompensed with the jingling of 

 the money, as the man had been satisfied by the smell of the 'cook's 

 meat. 



It need scarcely be said, that if the vapour from alimentary sub- 

 stances be capable, in any manner, of serving the purposes of nutrition, 

 it can only be by passing into the blood-vessels of the lungs. 



3. PHYSIOLOGY OF OLFACTION. 



In order that the sense of smell may be duly exercised, it is neces- 

 sary that the emanation from an odorous body shall not only impinge 

 upon the pituitary membrane, but that it shall do so with some degree 

 of force. It must, in other words, be drawn in with the inspired air. 

 Perrault 3 and Lower 4 found, that by making an opening into the tra- 

 chea of animals, and preventing the inspired air from passing through 

 the nasal fossae, smell was not effected; and that dogs, which were the 

 subjects of the experiment, readily ate food they had previously re- 



1 The Discovery of a New World, or a Discourse tending to prove, that 'tis possible there 

 may be another Habitable World in the Moon, with a Discourse concerning the possibility 

 of a passage thither. Lond., 1638. 



* Holy State, London, 1640. 



3 Ess. de Phys., iii. 29. 



4 Needham, de Format. Fcetus, p. 165; and Haller, edit, cit, v. 173. 



