V01CB OK MAMMALS.] 



UXDULATORY FORCES. ACOUSTICS. 



289 



movement in the larynx, associated with the articulate 

 movements. In short, stammering is a temporary spas- 

 modic affection of the glottis. For the prevention oi 

 stammering, the proper plan is to endeavour to bring 

 the associated movements of the larynx, with the organs 

 of speech more undfer the command of the will. To 

 sini: words is one method of obtaining this effect ; since 

 in singing, more attention is directed to the action oi 

 the larynx than in ordinary speaking. Moreover, it is 

 observed, that persons who stammer, pronounce better 

 in singing than in mere speaking. The raising of the 

 point of the tongue towards the palate has some effect 

 in counteracting this habit ; and this elevation of the 

 tongue seems to have been the object of the plan prac- 

 tised by the ancients, of placing bodies, such as pebbles, 

 under the tongue. Miiller recommends, for the cure of 

 stammering, that the patient should practise himself in 

 reading sentences in which all the letters which cannot 

 be pronounced without a vowel sound namely, the 

 explosive consonants, 6, d, g, p, <, and k are omitted, 

 and only those consonants included which are su 

 tible of an accompanying intonation of the voice. He 

 also directs that all those letters should be very much 

 prolonged. He says that, by this means, a mode of 

 pronunciation will be attained, in which the articulation 

 intly combined with vocal : -*ation, and the glottis, 

 neatly, never closed. 



As already mentioned, dumbness is dependent, not on 

 feet of the organs of speech, but on the absence of 

 .'. By assiduous efforts, deaf-mutes learn the 

 i.-nts of articulation by means of their sight. The 

 which they acquire is most commonly harsh, 

 Hiving to tlie want of the sense of hearing to regulate 

 their articulation. There was no discovery hailed with 

 interest than that of teaching the dumb to speak ; 

 and undoubtedly, harsh though the sounds be and yet 

 they are not always disagreeably harsh there can Irinlly 

 be a greater triumph of human art. It will hardly be 

 believed that some innovators on the education of the 

 deaf and dumb, seek to abolish the practice of teaching 

 them to articulate, on the ground that their harsh speech 

 is unfitted for the uses of society, and that they can 

 communicate witli their fellows sufficiently by other 

 as by speaking on the fingers and by writing. 

 This is a most unwarrantable view of the case of these 

 unhappy persons, particularly when they belong, as by 

 far the major part of them must do, to the labouring 

 classes of society. We have only to consider how many 

 persons there are in the condition of a labourer who can- 

 not write, or read writing, to be satisfied that this inno- 

 vation on the education of the deaf and dumb, should bo 

 at once put down in every institution in which it has 

 gained a footing. There is every reason to believe, that 

 in proportion as a knowledge of the mode in which tHe 

 sounds of the human voice in speech are produced, be- 

 comes better understood, the artificial articulation of the 

 deaf and dumb will become gradually less harsh and dis- 

 agreeable. 



,'irative Physiology of Voice. Organs of voice oc- 

 cur among inferior animals, in the mammalian tribes, 

 birds, and reptiles. In mammals, the organs of voice bear 

 a close resemblance to those <>f man. In birds, consider- 

 able moderations occur in these organs. In reptiles, 

 the apparatus of voice is of greater simplicity. 



Voice of Mammals. Among mammals, some are mute ; 

 and yet these are not always deficient in those parts of 

 the larynx which are most essential to voice. 



Among the orders which compose the class mammalia, 

 the cetaceans, consisting chiefly of the whale tribe, are 

 often described as mute. These animals, however, are 

 not mute altogether, but possess only a single lowing 

 note, or, at the utmost, they have the power of simply 

 bellowing. There are two distinct sections of cetaceans. 

 The first includes what have been termed the herbivorous 

 cetaceans, such as the sea-cow, the representative of the 

 ]i:i/iiilnr mermaid, and the dugong. The second order 

 includes the common cetaceans, popularly known ;i* 

 blowers. The act of blowing, from which they derive 

 their name, consists in the expulsion of water by the 

 vol. I. 



nostrils ; that is, along with their prey they receive a 

 large quantity of water into the mouth, and, while the 

 mouth remains closed, they blow out this superfluous 

 water by a hole in the upper part of the head. 



This expulsion of water is produced by means of a 

 peculiar arrangement of the veil of the palate. The 

 water accumulates in a sac situated at the exter- 

 nal orifice of the ca- Fig. 19. 



vity of the nose, whence, 

 by the compression of 

 powerful muscles, it 

 is violently expelled 

 through a narrow aper- 

 ture pierced on the sum- 

 mit of the head. By 

 this contrivance these 

 animals throw forth 

 those jets of water which 

 are seen by mariners at 

 a great distance. The 

 larynx has a pyramidal 

 form (see Fig. 19), and 

 penetrates into the pos- 

 terior portion of the 

 nostrils to receive air, 

 and conducts it to the 

 lungs, without the ani- 

 mal being obliged to 

 raise its head and mouth 

 above water for the pur- 

 pose. As there are no 

 projecting lamime in the 

 glottis, they can hardly 

 be said to have the pro- 



per organs of voice; and ,,, , TOSOl , E> ,,,, A!(1 , 

 thusthe noise they make RT.II o ronp.,nr. Hiueum of 

 may be described as a 



Fig. 20. 



pi ration. 



The larynx, however, in these animals is highly de- 

 veloped in other respects. 



Among the animals commonly described as mute, Is 

 the giraffe or cameleopard, termed by naturalists 

 Cameleo-pardalia girnffa. In the giraffe the vocal liga- 

 ments appear to be absent. 



The armadillo (Dcuyptu) is another of the mammalians 

 described as mute. The only peculiarity of the larynx 

 which has been observed is, that the epiglottis, or valve- 

 ike cartilage of the larynx, is bi-lobed. The armadillo, 

 t will be remembered, is remarkable among mammals 

 :or the scaly, hard, bony shell, composed of pavement- 

 like compartments, which cover the 

 lead, the body, and even the tail. 

 These animals belong to the order 

 termed Edentata. They live in 

 Mirrows, which they excavate. To 

 ;he Edentata also belong the ant- 

 eaters (Myrmecophagai), which are 

 regarded as mute. In the same 

 order is found the sloth (Bradypus 

 ridactylus). In this animal, how- 

 ever, vocal ligaments are found, 

 ,nd the windpipe is convoluted. 

 The voice is a plaintive melody, 

 consisting of an ascending and de- 

 scending scale of the hexachord. 



Amongthe Rodentia, or gnawers, 



he common porcupine of Europe is 



mute. In this animal it has been 



ascertained that there are no vocal 



igiiments. 



Such, then, are a few examples I.ABVNX OF CAM*.. LAID 



>f the animals in the class Mam- 



.. . . . id, epiglottis ; A. superior 



malia which are mute, or nearly so. ' V0( ! a f cor(lg \ '_ in feYi,, r ; 



In the order Ruminantia, we find d, ar> tenoid cartilages; 

 animals possessed of a sonorous MEftSEi *' ^ 

 voice, exempl ilieil particularly in the 



In the ox, the larynx is well developed ; there are no 

 upurior vocal ligaments, but the inferior or true voc v 



2 p 



