ANIMAL PHYSIOLOGY. 



225 



I.MAI. PHYSIOLOGY. VII. 

 Tin. . if DOLL, 



IN the pri- i'.-s on the organs of sight and hearing 



it waa remarked that while the sensations excited through their 

 agency wore HO ditlVri-ni, thu external causes which operated on 

 the eye and ear respectively wore not dissimilar. Rapid vibra- 

 tions, propagated by bodies themselves in violent but otherwise 

 ilnution, are convoyed through inti-rvnnir,' modia 

 for great, oiid, in the case of light, unlimited distances, by 

 Waves which are capable of indicating tho direction from which 



neoted with mental operations. Their nses hare 

 to our animal than to oar intellectual life, and the appetite* 

 arise from a daeire to gratify thsss ssnsss have always 

 been oonsidered to be lees refined and move sensual than those 

 which pertain to the senses of sight and hearing. It is true 

 that a spurious delicacy and refinement of the sense of smell 

 have caused the wealthier elaesee in time* of high civilisation 

 to delight in costly and rare essences and scents; but the 

 extenaivu use of these has been the characteristic of 

 races, and of times when civilisation, in its highest MOM, 

 begun to succumb to luxury. When Borne boasted of 



J. VERTICAL SECTION OF HUMAN HEAD, SHOWING THE BELATION OP THE PASSAGES FOE AIB AND FOOD. II. FRAMEWORK or THT Voex. 

 III. MUSCLES OF THE NOSE. IV. SEPTUM OF THE NOSE AND ITS NERVES. 



Ecf. to NOB. in Figs. I. 1, upper turbinated bone ; 2, middle do. ; 3, lower do. ; 4, hole leading to the canal which drains the eye; 5, Eusta- 

 chian hole ; 6, palate ; 7, uvula ; 8, epiglottis ; 9, pharynx ; 10, larynx ; 11, cricoid cartilage ; 12, thyroid cartilage ; 13, cavity of the 

 mouth. II. 1, part of upper jaw bone ; 2, nose bone; 3, upper side cartilage ; 4, lower do. ; 5, cellular tissue. III. 1, pyramidal mnsel* 

 of the nose ; 2, muscle to lift the side cartilages ; 3, compressor of the nose ; 4, front dilator of the nostril ; 5, small compressor of the 

 nostril ; 6, hind dilator of the nostril ; 7, muscle to pull down the side cartilages. IT. 1, nerve of the lobe of nose ; 2, olfactory lobe ; 

 3, nerves of the septum ; 4, nerve of palate. 



they proceed. These vibrations, therefore, can inform the mind 

 concerning objects far removed from its instrument, the body, 

 with an accuracy which makes us scorn tho idea that we can be 

 deceived in that which our eyes have seen and our cars heard. 

 Through those avenues the human mind extends itself, till it 

 touches, and by the aid of reason may be said to grasp, the 

 universe ; and the highest powers of the mind are employed 

 in interpreting tho messages brought to us by light and 

 sound. 



In marked contrast to these are tho remaining senses of 

 which we have to write namely, those of smell, taste, and 

 touch. These senses are excited by material particles applied 

 directly to those ports of tho body which can take note of their 

 peculiar qualities, and henco they are for less necessarily con- 



YOL. I. 



costly perfumes, she had almost ceased from the prouder boast 

 of being mistress of the world ; and tho more manly tone of 

 modern and western society has decided between Hotspur and 

 the fop, to the prejudice of the latter. 



Matter or material substances exist in three forms tho solid, 

 liquid, and gaseous ; and almost all substances can be made to 

 assume each of these forms. Thus ice may bo transformed 

 into water and into steam. When the particles of matter 

 hang together so closely and rigidly that they will not move 

 over one another without the application of force, they form a 

 solid. When the particles hang together so loosely that they 

 will move over and round each other with the slightest force, 

 so that they can scarcely be said to hang together at all, tha 

 substance is called a liquid. When the particles not only do 



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