REFLEX ACTION' AND DISEASE. 643 



pathetic nerve. A stroke upon the belly will through these nerves 

 stop the heart, dilate the vessels, and induce the most serious con- 

 ditions of shock, killing the patient, or at any rate bringing him down 

 to death's door. The most important nerves through which the vessels 

 are reflexly contracted are the splanchnics, and the contraction of the 

 abdominal vessels which they supply has much more effect in altering 

 the general pressure of blood throughout the arterial system than the 

 contraction of any other vascular district in the body. But although 

 the abdominal vessels are the clrief ones concerned in alterations of 

 blood-pressure, yet local alterations in the various organs may have an 

 even more powerful action upon the nutrition of these organs them- 

 selves ; for it is probable that although the abdominal vessels may be 

 caused to contract by powerful stimulation of almost any sensory nerve, 

 yet that the blood-vessels in different organs of the body — such as, for 

 example, the kidneys or mucous membranes — are more affected by 

 irritation of some nerves than of others. The researches of Sanders- 

 Ezn have shown that stimulation of certain sensory nerves, or of limited 

 districts of the skin, will induce definite muscular action due to con- 

 traction of limited groups of muscles. It is probable that irritation of 

 limited districts of the skin also induces contraction of limited groups 

 of involuntary muscular fibers or of limited districts of vessels. It is 

 well known that tonsillitis is much more frequently produced by expo- 

 sure to a draught which strikes the back or side of the head than by a 

 current of air meeting one full in the face, or even by long-continued 

 exposure to a storm in the open air. The cause of this has not yet 

 been satisfactorily ascertained, but it has been attributed with some 

 probability to irritation of the nerves of the ear by the cold current of 

 air. When the throat is irritated, the irritation is not unfrequently felt 

 in the ear; and, vice versa, it seems probable that irritation in the ear 

 may cause alterations in the throat. It has been observed that pressure 

 upon the floor of the external auditory meatus in a person who had 

 suffered from otorrhoea produced violent or uncontrollable coughing ; 

 and, if irritation of the ear thus produces a motor reflex like that of 

 irritation of the larynx, it seems probable that it may also produce a 

 reflex trophic disturbance similar to that which would have followed 

 the direct application of an irritant to the larynx. 



Congestion of the kidneys in horses is caused b}' exposure of the 

 loins to rain, the action of cold upon that district of the general sur- 

 face having a peculiar effect upon the kidneys, not produced by its 

 application to other parts of the body. It is stated by Sidney Ringer, 

 upon Brown-Sequard's authority, that blistering the loins will cause 

 contraction of the vessels of the kidney, but I have not been able to 

 verify this quotation. But, though there seems to be a peculiar relation 

 between the loins and the kidne}'-, the renal circulation would appear 

 to be affected by other nerves. Thus, for example, in a case narrated 

 by Dr. Griffith at a meeting of the Medical Society of London, albu- 



