- Virulent smells—including such odors as that of opium, “Odor cimicis,” etc.
- Nauseating smells—including the odors of decaying animal matter, of feces and the like.
The pungency of smells is not an olfactory quality, but is due to the excitation of filaments of the trigeminus, which are freely distributed in the Schneiderian membrane. The sensation is more like pressure than smell. When very strong it becomes a tickling, and sneezing ensues. Persons who have congenital or pathological defects of smell are said to have cultivated these sensations by attention to such an extent that they do duty for smells proper,[1] Some smells which are not the flavors of food sensed in expiration, seem to be tastes, as well as smells, For example, we think of the odor of boiling syrup as sweet, and say that curdled milk “smells” sour. This is probably due to early 1as80ciation, which has indissolubly fused certain taste-memories with certain smell-sensations of peripheral origin.[2] It may, however, be due to the entrance of sapid particles through the nose into the pharynx.[3] Smells are often blended with pressure sensations other than pungency and with temperature sensations.[4] It is probable that there is an element of pain in an impression of pungency, while smells often give a “feeling of weight,” pure and simple. Whenever the subjects in these experiments spoke of the heat, taste, pressure, pain, or pungency of an odor, their remarks were carefully noted, on the supposition that such factors in the total impression were disturbing in a quantitative investigation of olfactory qualities proper.
Zwaardemaker's differentiation of the specific energies of
smell and localization of their actions on the olfactory mucous membrane is not to our present purpose. We may simply note in passing that he arranges the zones of their operation in horizontal order, since the height to which the air current is carried in the nose makes no difference in the quality of an odor ; and that he rather ingeniously places the nauseating and virulent smells farthest back and closest to the pharynx, in a region where they may excite the reflexes of vomiting and coughing by mere irradiation of nervous excitation without the connecting link of central processes ; puts the hircine and ambrosiac odors in the middle, on account of the connection of hyperaemia of the “corpora cavernosa nasalia” with the blood supply of the generative organs ; and locates the fragrant, aromatic and ethereal smells farthest to the front, since the
