LOCOMOTOR MECHANISMS. 829 



EXPLOSIVES. Labials, without voice P. 



with voice B. 



Dentals, without voice T. 



with voice D. 



Gutturals, without voice K (hard C). 



with voice G- (hard). 



ASPIRATES. Labials, without voice F. 



with voice V. 



Dentals, without voice L, S (soft C), Sh, Th (hard). 



with voice Z, Zh (in azure, the French j), 



Th (soft). 



Gutturals, without voice CH (as in loch}. 



with voice GrH as in lough), 



RESONANTS. Labial, M. 



Dental, N. 



Guttural, NG-. 



VIBRATORY. Labial, not known in European speech. 

 Dental, R (common). 

 Guttural, R (guttural). 



770. Whispering is speech without any employment of the vocal cords, 

 and is effected chiefly by the lips and tongue. Hence, in whispering the 

 distinction between consonants needing and those not needing voice, such as 

 B and P, becomes for the most part lost. 



LOCOMOTOR MECHANISMS. 



771. The skeletaj muscles are for the most part arranged to act on the 

 bones and cartilages as on levers, examples of the first kind of lever being 

 rare, and those of the third kind, where the power is applied nearer to the 

 fulcrum than is the weight, being more common than the second. This 

 arises from the fact that the movements of the body are chiefly directed to 

 moving comparatively light weights through a great distance, or through a 

 certain distance with great precision, rather than to moving heavy weights 

 through a short distance. The fulcrum is generally supplied by a (perfect 

 or imperfect) joint, and one end of the acting muscle is made fast by being 

 attached either to a fixed point, or to some point rendered fixed for the time 

 being by the contraction of other muscles. There are few movements of the 

 body in which one muscle only is required ; in the majority of cases several 

 muscles act together in concert ; nearly all our movements are coordinate 

 movements. Where gravity or the elastic reaction of the parts acted on does 

 not afford a sufficient antagonism to the contraction of a muscle or group of 

 muscles, the return to the condition of equilibrium is provided for by the 

 action either elastic or contractile of a set of antagonistic muscles ; this is 

 seen in the case of the face. 



772. The erect posture, in which the weight of the body is borne by 

 the plantar arches, is the result of a series of contractions of the muscles of 

 the trunk and legs, having for their object the keeping the body in such a 

 position that the line of gravity falls within the area of the feet. That this 

 does require muscular action is shown by the facts, that a person when stand- 

 ing perfectly at rest in a completely balanced position falls when he becomes 

 unconscious, and that a dead body cannot be set on its feet. The line of 

 gravity of the head falls in front of the occipital articulation, as is shown 

 by the nodding of the head in sleep. The centre of gravity of the combined 

 head and trunk lies at about the level of the ensiform cartilage, in front of 

 the tenth dorsal vertebra, and the line of gravity drawn from it passes 

 behind a line joining the centres of the two hip-joints, so that the erect body 



