268 Dr. A. P. W. Philip oti the 



small portions to the muscles ; to the latter, from every part of 

 the brain and spinal marrow through a chain of ganglions 

 which, on the one hand, communicate with every part of these 

 organs, and, on the other, with all the muscles of involuntary 

 motion ; in the former instance, the influence of the nervous 

 system being the only natural stimulus, in the latter, other 

 stimuli exciting the muscle to its usual function, and the influ- 

 ence of the nervous system, being only occasionally bestowed 

 on it for purposes which we shall soon have occasion to 

 consider. 



When the nerves of a muscle of voluntary motion are divided, 

 the supply of the stimulus on which its function depends 

 being cut off", it is rendered paralytic, not because its power is 

 impaired, for it is as sensible to the effects of stimuli as while 

 its nerves were entire, but because the channel of the only stimu- 

 lus by which the will operates on it is obstructed, and here the 

 effect of the division of these nerves ends. The consequence is 

 very different, when the nerves of the muscles of involuntary 

 motion, the ganglionic, are divided. 



If the principal ganglionic nerves, the eighth pair through 

 which the influence of the brain is chiefly supplied to those 

 muscles be divided, the function of the muscles appears to be 

 wholly unaffected by it. The heart and vessels support the cir- 

 culation as well as before the division of the nerves. For this 

 result we are prepared by what has been said of these muscles. 

 An evident disorder, however, in the secreting power of some 

 of the vital organs immediately ensues. The stomach no longer 

 secretes a fluid capable of producing the necessary change on 

 the food*, while the fluids of the lungs deviate from the healthy 

 state, and accumulate in the bronchiie and air cells. The struc- 

 ture of the lungs itself, in the space of a few hours, becomes 

 evidently diseased, and the animal dies of dyspnoea ; failure in 

 the office of the lungs, necessarily proving more suddenly fatal 

 than failure in that of the stomach. It has been questioned, 

 whether the effects on secreting surfaces of dividing the eighth 

 pair of nerves should be ascribed to the interruption of the 



* Exp. Inq. Chap, 5. 



