128 Mr. Lc Gros Clark on the Mechanism of Respiration. 



contract, without reference to the cooperating or antagonistic action of 

 other muscles. Such isolated experiments are therefore not only unsatis- 

 factory, but often delusive. 



Fig. 1. 



But the question which I have raised may be discussed a little more in 

 detail. The inferior angle of the scapula reaches as low as the eighth rib, 

 while the thorax is in a state of repose after an ordinary inspiration. The 

 lowest digitation of the serratus magnus, arising from the extreme end of 

 the angle, follows the course of the eighth rib,' and is attached to it. 

 Assuming for a moment the capability of the serratus magnus to act in 

 inspiration, it would be necessary for this result that the vertebral costa of 

 the scapula be drawn back and rigidly fixed by the rhomboids &c. ; the 

 consequent extension of the fibres of the serratus is further enhanced by 

 the expansion of ti e chest during forced inspiration — a condition which is 

 not consistent with what is observed in other muscles during a passive 



