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. Liégeois’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 
