ODORS AND LIFE. 183 



diffused through the mass of the water. Aromatic essences 

 produce a like effect. Though insoluble in water, they have 

 a powerful tendency to disperse themselves throughout it ? 

 and water that receives a very small quantity of the odor- 

 iferous principle, in the shape of extremely fine powder, 

 has enough to gain their perfume completely. Li^geois's 

 experiments give proof of the most diligent labors and of 

 praiseworthy sagacity. Science has accepted them with 

 satisfaction, and, after employing them usefully, will pre- 

 serve the memory of their author, taken away in the flower 

 of his age, at the outset of a noble career as a physiologist 

 and surgeon. 



It seemed, to quote his words, as though in these ex- 

 periments we were assisting at the formation of the odor- 

 ous molecules. Those delicate atoms emitted from odorous 

 substances and diffused through the atmosphere, are in 

 fact the very same that impinge on our pituitary mem- 

 brane, and give us the sensation of odors. Moreover, facts 

 long ago observed display this revealing action, so to call 

 it, of water upon odors. At morning, when the verdure is 

 moist and the flowers covered with sparkling pearls of 

 dew, a fresher and balmier fragrance exhales from every 

 plant. It is the same after a light shower. Vegetation 

 gains heightened tints, at the same time that it diffuses 

 more fragrant waves of perfume. We remark an effect of 

 the same kind in the physiological phenomenon of taste. 

 The saliva serves as an excellent vehicle for diffusing the 

 odorous principles ; then the movements of the tongue, 

 spreading that fluid over the whole extent of the cavity of 

 the mouth, and thus enlarging the evaporating surface, are 

 clearly of a kind to aid the dispersion of the odorous prin- 

 ciples, which, as we have seen, take a considerable part in 

 the perception of tastes. 



Now, in the phenomena of smell, air acts in the place 

 of water. It seizes the odorous particles and brings them 



