58 HAND-BOOK OF PHYSIOLOGY. 



of which we may form some idea,, by recollecting that musical instruments 

 made of different materials, e.g., metallic and gut-strings, may be tuned 

 to the same note, but that each will give it with a peculiar tone or 

 "timbre." 



Varieties of Voices. The larynx of boys resembles the female 

 larynx; their vocal cords before puberty have not two-thirds the length 

 which they acquire at that period; and the angle of their thyroid cartilage 

 is as little prominent as in the female larynx. Boys' voices are alto and 

 soprano, resembling in pitch those of women, but louder, and differing 

 somewhat from them in tone. But, after the larynx has undergone the 

 change produced during the period of development at puberty, the boy's 

 voice becomes bass or tenor. While the change of form is taking place, 

 the voice is said to "crack;" it becomes imperfect, frequently hoarse and 

 crowing, and is unfitted for singing until the new tones are brought 

 under command by practice. In eunuchs, who have been deprived of 

 the testes before puberty, the voice does not undergo this change. The 

 voice of most old people is deficient in tone, unsteady, and moreflrestricted 

 in extent: the first defect is owing to the ossification of the cartilages of 

 the larynx and the altered condition of the vocal cord; the want of steadi- 

 ness arises from the loss of nervous power and command over the muscles; 

 the result of which is here, as in other parts, a tremulous motion. These 

 two causes combined render the voices of old people void of tone, un- 

 steady, bleating, and weak. 



In any class of persons arranged, as in an orchestra, according to the 

 character of voices, each would possess, with the general characteristics 

 of a bass, or tenor, or any other kind of voice, some peculiar character by 

 which his voice would be recognized from all the rest. The conditions 

 that determine these distinctions are, however, quite unknown. They 

 are probably inherent in the tissues of the larynx, and are as indiscernible 

 as the minute differences that characterize men's features; one often ob- 

 serves, in like manner, hereditary and family peculiarities of voice, as 

 well marked as those of the limbs or face. 



Most persons, particularly men, have the power, if at all capable of 

 singing, of modulating their voices through a double series of notes of 

 different character: namely, the notes of the natural voice, or chest-notes, 

 and the falsetto notes: The natural voice, which alone has been hitherto 

 considered, is fuller, and excites a distinct sensation of much stronger 

 vibration and resonance than the falsetto voice, which has more a flute-like 

 character. The deeper notes of the male voice can be produced only 

 with the natural voice, the highest with the falsetto only; the notes of 

 middle pitch can be produced either with the natural or falsetto voice; 

 the two registers of the voice are therefore not limited in such a manner 

 as that one ends when the other begins, but they run in^part side by side. 



Method of the Production of Notes. The natural or chest-notes 



