30.2 



comparison with the ranges of the solar diurnal variation (which are 

 known to follow nearly the same law as the law of mean disturbance), 

 that the mean lunar disturbance obeys the same law as the mean solar 

 disturbance, and that the former is probably dependent upon the 

 latter. 



III. " Experimental Researches on the Functions of the Vagus 

 and the Cervical Sympathetic Nerves in Man." By AUGUS- 

 TUS WALLER, M.D., F.R.S. Received June 6, 1861. 



The offices of these two nerves in the animal economy are of 

 such importance as to render it a matter of practical interest to 

 the physician, as well as to the physiologist, to obtain as clear an 

 insight as possible into their functions. It would be impossible to 

 point out any nerves presenting so many questions of daily importance 

 to the practitioner as these, which govern the innervation of the 

 stomach, the heart, the lungs, and the liver. 



Hitherto we have been restricted to their investigation in the lower 

 animals, and from the results which have been thus furnished, we 

 have judged of what obtains in man. It is almost needless for me 

 to point out that, although such inferences are generally correct as 

 regards the motor phenomena of life, our evidence respecting the 

 sensory functions of the nerves is necessarily more uncertain and 

 inconclusive. 



My object at present is to describe some results obtained by irri- 

 tating the vagus and cervical sympathetic in man, in such a way as 

 to ascertain their functions, not only in a state of health, but also 

 their condition in disease, and in various functional derangements to 

 which they are subject. 



The means which I adopt for this purpose are the same as that 

 which I have used in the case of the ulnar nerve and of the retina, 

 i. e. mechanical irritation by simple pressure on the trunk of the 

 nerve. I generally apply pressure of the fingers at the highest point 

 of the neck behind the ramus of the lower jaw. A moderate amount 

 of pressure applied in this manner is usually sufficient, in the course 

 of about a minute, to produce symptoms which are at once easily re- 

 cognized as originating from the irritation of the vagus and the sympa- 

 thetic nerve. 



