266 Dr. A.P.W. Philip o/w/^e 



muscles of involuntary motion being subject to the influence of 

 every part of these organs. We cannot suppose that they 

 i-eceive nerves from every part of them. We know, indeed, that 

 no organ does so. The following seems to be the state of the 

 question. We see some parts influenced by every part of the 

 brain and spinal marrow ; others only by small parts of them. 

 In the latter instances, we see directly proceeding from those 

 small parts the nerves of the part influenced. In the former 

 instance, namely, where the partis influenced by all parts of the 

 brain and spinal marrow, we do not see nerves going directly 

 from all parts of these organs to the part influenced, but we 

 see this part receiving nerves from a chain of ganglions to 

 which nerves from all parts of them are sent. It is, therefore, 

 evident, from direct experiments, that the nerves issuing from 

 ganglions convey to the parts, to which they send nerves, the 

 influence of all the nerves which are received by these bodies. 



Such then is the relation which the most important organs of 

 involuntary motion bear to the brain and spinal marrow. Their 

 powers are not directly dependent on either, yet they are subjected 

 to the influence of every part of both, communicated through 

 the medium of the ganglions; and when we see the other organs 

 of involuntary motion equally independent of the brain and 

 spinal marrow, and supplied with nerves from ganglions, in the 

 same way with the former, it is impossible not to infer, that they 

 bear the same relation to the nervous system. Thus, it would 

 appear, that the ganglions may be regarded as a secondary 

 centre of nervous influence, receiving supplies from all parts of 

 the brain and spiral marrow, and sending to certain organs the 

 influence of all those parts. 



If the nervous influence of the thoracic and abdominal viscera 

 be thus supplied from a common source, why, in aflfections of 

 the spinal marrow, it may be asked, is the breathing most influ- 

 enced when the disease is in the dorsal portion of this organ* 

 and the action oT the bladder and rectum, when its chief seat is 

 in the lumber portion? This necessarily arises from the inter- 

 costal muscles deriving their nerves from the dorsal, and the 

 abdominal muscles from the lumber portion of the spinal mar- 



