OF VOICE. 83 



Ossification docs not result, as we have already noticed, from the transformation of 

 cartilage into bone. The diaphysis of the long" bones, and the centre of the large 

 bones, which are amongst those first formed, pass immediately from a mucous to an os- 

 seous state. The other parts of this structure have an intermediate cartilaginous con- 

 dition ; and it is in these parts that the successive stages of ossification may be best ob- 

 served. 



The cartilage which, for a longer or shorter period, supplies the place of bone, be- 

 comes at first hollowed into irregular cavities, afterwards into canals lined with a vascu- 

 lar membrane and filled by a mucilaginous and viscid liquid ; these canals become red, 

 the cartilage now assumes an opaque appearance, and ossification commences towards 

 its centre. The first point of ossification is always in the centre of the cartilage, and 

 never at its surface. This point is surrounded by a reddish cartilage, and that part 

 which is nearest it is opaque and pierced with canals still farther than opacity reaches. 



The osseous point augments progressively by means of additions on its surface, as 

 well as by an interstitial deposit in its substance. The cartilage gradually becomes 

 hollowed by cavities and canals, lined by a vascular sheath, diminishes as the ossifica- 

 tion extends, and disappears altogether when the process is completed. 



With respect to the state in which the osseous matter is formed, we are inclined to 

 agree with Mr. Beclard, in the opinion that the earthy matter is deposited, in a fluid 

 condition, and at the same time with animal matter, jn the organized tissue which se- 

 cretes it. Its subsequent solidification arises either from the deposition of a larger pro- 

 portion of earthy matter, or from the absorption of the vehicle which gives it the fluid 

 condition ; or from the joint operation of both these causes. 





Of Voice. 

 Note HH*. 



The cricoid cartilage, which supports the two arytenoid cartilages, is not immovea- 

 ble at the inferior part of the larynx. The trachea to which it is attached by its inferior 

 margin, yields and elongates itself in order to allow it motion. The muscles of the 

 Sarynx do not contribute to the production of the voice solely by means of the action 

 which they exercise on the sides of the glottis ; several of them, and particularly the 

 thyro-arytenoids, may be considered as forming part of the parietes of this opening. 

 These small muscles give rise to acute sounds by drawing closer the two arytenoid car- 

 tilages, and when in a state of contraction they also seem susceptible of a vibratory uio- 

 tion, varying iu degree according to the degree of contraction : by the assistance, there- 

 fore, of the muscular fibres covering its sides, the glottis is susceptible of vibrations 

 snalagous to that of the lips applied to the opening of a French-horn. The production 

 of sound is owing to the action of the muscles of the larynx on its cartilages, during ex- 

 piration ; and whatever impeds the functions of the nerves actuating these muscles, 

 puts a stop to the utterance of sound. 



Of Ventriloquism. Various attempts have been made to explain the manner in which 

 the ventriloquist is enabled to modify his articulations into the semblance of distinct 

 voices. Dr. Good considers ventriloquism " to be an imitative art, founded in a close 

 attention to the almost infinite variety of tones, articulations, and inflexions, which the 

 glottis is capable of producing in its own region alone, when long and dexterously 

 practised upon ; and a skilful modification of these vocal sounds, thus limited to the 

 glottis, into mimic speech, passed for the most part, and whenever necessary, through 

 the cavity of the nostrils, instead of through the mouth." He farther supposes that 

 " some peculiarity in the structure of the glottis, and particularly in respect to its mus- 

 cles and cartilages," is requisite to carry this art to perfection. The explanation -/rhich 

 Magendie otters on this subject, appears to us to be more correct, although perhaps not 

 sufficiently so. This physiologist asserts, that ventriloquism consists in certain modifi- 

 cations of sounds or speech, produced by a larynx of the common formation, with a 

 strict attention to the different effects of sound thrown at different distances, and 

 through different modes of conveyance. We cannot agree with Dr. Good that the 

 ventriloquist performs articulation by means of the larynx only, although we may con- 



