290 ON THE SENSES. 



distance of many miles, and finds it by following the smell ; tlie wind conveys 

 to the game the exhalation of man over a large tract of land; it is the smell 

 which, in the pairing season, brings together the males and females of a large 

 number of animals, thus playing an important part also in the preservation of 

 the species. With man, it is true, the functions of the nose are less conspicuous 

 and apparently of less vital importance ; but though he makes no use of it for 

 finding out his nourishment or his enemies, still its vocation is not restricted to 

 causing delight to the soul by sweet odors. Is it necessary to ndduce special 

 examples to show in how many ways we are indebted to our sense of smell for 

 information regarding the presence or absence of substances or certain proceed- 

 ings in the outer world, from which all kinds of judgments and actions may 

 occasionally result? We shall specify only one side of our nasal activity. The 

 organ of smell is frequently designated as a guard of respiration, as it informs 

 us about the quality of the air which we inhale, and teaches us to shun certain 

 noxious irrespirable gases, which are distinguished by a peculiar odor. This 

 designation ought not to be misunderstood, nor the importance of that office over- 

 estimated. First, there is a number of irrespirable gases which produce no 

 sensation of smell, against the inhaling of which, therefore, the nose is incapable 

 of warning us. Secondly, it must be observed that the quality of a sensation 

 of smell does not directly indicate the noxious or innoxious character of a certain 

 gas, or of a certain admixture in the atmosphere, but that in order to find this out 

 we must have acquired by other means the necessary experience concerning the 

 effects of gases and vapors characterized by peculiar odors. Were we to form our 

 judgment according to an idea immediately attaching itself to our sensation, and 

 thus believe all agreeable impressions of smell to be innocent or useful, and all 

 disagreeable ones to be injurious, we would fall into quite dangerous deceptions; 

 for instance, we woixld be inclined to sip prussic acid without hesitation. Thirdly, 

 we must still remark that we recognize a number of noxious aerial substances by 

 the nasal sense of touch, and not by that of smell, and that these sensations of 

 touch, on account of their highly disagreeable quality, more easily persuade us to 

 avoid the inhaling of those gases than would the sensations of smell. Those 

 pungent sensations of touch which are produced in the nose by the vapors of 

 sulphur leave us not a single moment in doubt whether we shall inhale those 

 vapors or not, and they would prevent us from inhaling them even if we 

 knew them to be conducive to our health. In this limited sense only the organ 

 of smell deserves the title of guard of respiration. 



This much, or rather this little, dear reader, do we know of the sense of 

 smell. We have candidly unveiled the weak sides of physiology, being con- 

 vinced, as we have stated, that it must be of great use to the common reader to 

 learn what we do not know, and that it is a merit to show the erroneous charac- 

 ter of popularly current physiological notions, even when we are unable to replace 

 them by exact truths. May our reader share Avith us the hope that the power 

 of science, so nobly developed in our age, may once, and perhaps ere long, lift 

 the veil still unpenetrated, and, according to some desponding minds, eternally 

 impenetrable, which covers the mysteries of nervous life. Though the soul, the 

 immaterial principle, must forever remain a noli me tangere of physiological 

 research, the machinery by which it works will once lay open before the eye of 

 physiology with all its innermost recesses and finest particles. We would not 

 like to quarrel with the most genial of our poets, but it grates on our ear to 

 hear Faust thus despairingly speak of nature. What it reveals not to thy spirit 

 thou canst never extort with levers and screws. A little bat essential alteration 

 of this sentence will make it the device of the physiologist, with which he will 

 calmly follow the trace of the highest problems. Our device is : Thou must 

 extort it with levers and screws ! The microscope, the chemical balance, and 

 other manifold and ingenious apparatus which fill the armory of the physiolo- 

 gist, are our lever, our screw. 



