THE SENSE OF SMELL. 285 



in the moisture of the cuticle, and as it would seem proper to assume that such 

 a substance would preserve, in a liquid solution, all its essential qualities. The 

 question is not so easily solved as would appear at the first glance, and 

 therefore not yet solved with complete certainty. In a surprising way the 

 experiments made prove more against than in favor of the smellability of odorous 

 substances in liquid solution; but as in most cases there is a strong presumption 

 of the possible existence of other reasons for inodorousness than the state of 

 solution, no decided judgment ought to be formed. We shall only briefly indi- 

 cate the way of proceeding, whac regards must be had, and what precautions 

 taken. Were we only to wet the cuticle of the nose with the liquid solution of 

 an odorous substance, we could by no means conclude from the resulting sensa- 

 tion of smell that the liquid solution has been effective, as while, besides it, 

 there is air in the nasal cavity, a part of the odorous substance combines with 

 it, thus coming in contact with the cuticle also in an aerial state. The first 

 cxjudition of such experiments will, therefore, be to exclude from the nasal cavity 

 all air which could absorb a part of the odorous substance from the solution, 

 and to fill up with the latter the whole cavity. Such a filling up of the nose 

 with liquid will probably appear to our readers not only as a very disagreeable 

 experiment, but also as impracticable. Neither the one nor the other is really 

 the case, as we can assure from experience ; the experiment is very easily made, 

 and neither painful nor in any other way particularly disagreeable ; it by no 

 means belongs to the list of torturings with which physiologists are so eagerly 

 reproached. Let one man recline upon a long table and so hang down his head 

 oS the edge as to have the nostrils turned upward, and another will be able to 

 completely fill up each of the latter with water abundantly poured into them. 

 The liquid remains in the nostril as in a tumbler, without flowing down, as we 

 would expect, into the throat, which is in open communication with the nasal 

 cavity, of which breathing through the nose alone is a sufficient evidence. The 

 mechanism which interrupts this communication, and forms a close partition 

 between the nasal and guttural cavities, is the following : \Vhen looking into 

 the wide-open mouth of a man, pressing down the back of the tongue with our 

 finger or v/ith a spoon, and thus glancing beyond it, we perceive in the back- 

 ground of the oral cavity an arched gate, leading into the guttural cavity, so 

 that, with the help of a favorable illumination, we can see through the gate the 

 hind wall of the throat. Hanging down into this gate like a curtain there is a 

 soft fold of skin, with a prolongation in its middle, known as the uvula, which, 

 reaching down almost to the threshold of the gate, divides this into two halves. 

 This perpendicularly hanging-down fold, which is moved by peculiar muscles, 

 can be bent down backward so as to stand horizontally, the uvula touching the 

 wall of tl'ie throat. In this position the soft palate forms a valve entirely closing 

 the throat, so that nothing 'can pass from the latter into the interior openings 

 of the nasal cavity above it, or vice versa. This separation of the two cavities 

 through the described mechanism takes place every time on the swallowing of 

 food or beverage, which are by this means prevented from straying into the 

 nasal cavity; it is the same valve which, in the experiment in question, prevents 

 the flowing down to the throat of the water poured into the nostrils. Now, if 

 we in this way fill the nasal cavity with water, mixed with a small quantity of 

 eau de Cologne, of which it smells when held before the nose, a sensation of 

 smell arises at the time of the pouring in of the liquid, and vanishes when 

 the filling up is complete. This might appear at first glance as an unequivocal 

 evidence of the odorlessness of the odorous substances when brought in contact 

 with the cuticle of the nose in liquid solution, and thus also of the necessity of 

 their being in a gaseous state for the purpose of smelling; but considerable 

 doubts arise against this conclusion. Microscopic examinations of the cuticle 

 of the nose have shown that the vesicles Avith which the latter is internally 

 liuedrf and which seem to perform such an important mediating part between the 



