6 



ent animals, as regards the energy of their reflex power, are 

 to be explained by anatomical differences. There exists a con- 

 stant relation between the degree of the reflex power and the 

 amount of grey matter in the spinal cord. It appears, also, 

 that the mode of circulation of the blood in the spinal marrow 

 has a great share in the causes of differences amongst different 

 animals. 



3. It is not necessary for the existence of the reflex power 

 that the spinal cord should be without alteration. I have found 

 the reflex faculty remaining in pigeons after I had crushed the 

 spinal cord, and produced in it a considerable alteration. This 

 is important to be known by practitioners, to prevent their 

 drawing the conclusion, from the existence of reflex action after 

 a fracture or a luxation of the vertebral column in man, that the 

 spinal cord is healthy. 



4. The influence of the nervous system on the secretions, by 

 a reflex action, has been very little studied. I will state two 

 examples of these reflex secretions : 1st, There is on the face, 

 and particularly on the forehead and the nose, an abundant pro- 

 duction of sweat when the nerves of the taste are strongly 

 excited, as they are, for instance, by common salt, pepper, sugar, 

 etc. In certain persons the quantity of sweat produced in such 

 cases is sometimes, even in the winter, very considerable. 2d, 

 I have observed that it is sufficient to excite the nerves of taste 

 in order to produce the secretion of gastric juice, bile and pan- 

 creatic juice. 



Ill RESEARCHES ON THE INFLUENCE OF THE NERVOUS SYSTEM 



UPON THE FUNCTIONS OF ORGANIC LIFE. 



My experiments have convinced me that if it is certain that 

 the nervous system is able to act, and frequently does act, on the 

 functions of organic life, it is not the less certain that the action 

 of the nervous system on these functions is not necessary. I 

 hope this will be sufficiently demonstrated by the numerous facts 

 I have to relate. 



a. Influence of the section of nerves on nutrition and secretion. 



1. The frequent occurrence of certain pathological changes 

 after section of the sciatic nerve in Mammals, has been cited as 



