532 THE THIRD HUXLEY LECTURE 



by nervous action. It may be doubted whether active congestion could alone 

 give rise to it, though it is by no means inconceivable that the excessive supply 

 of the nutrient fluid might in time exhaust the tissues by over-stimulation, 

 and so bring about more or less of that impairment of vital energy which we have 

 seen reason to regard as the essential cause of the blood-corpuscles lagging 

 behind the liquor sanguinis. 



Or it may be that the nerves produce this weakening effect upon the tissues 

 by immediate action upon them. From that point of view, the proof afforded 

 by the pigment-cells of the influence of the nerves over processes going on within 

 cells seemed to me peculiarly interesting. And we can conceive of nervous 

 impulse impairing their energies either by over-stimulation followed by ex- 

 haustion, or by immediate prostration of their powers as by an electric shock. 



That the latter idea is not altogether out of the question seems to follow 

 from a kind of experience familiar to surgeons. I will mention one instance 

 of this which produced a great impression upon me. A healthy man, in the 

 middle period of life, had been operated on by lateral lithotomy. All went 

 perfectly well till about ten days had elapsed, when the renal secretion, which 

 had passed through the wound since the operation, flowed for the first time 

 through the natural channel. In those days, when lateral lithotomy was the 

 routine treatment of calculus, it was well understood that the mucous mem- 

 brane becomes in a few days unaccustomed to the urine, which then acts upon 

 it with irritating effect, and the result may be a violent general nervous com- 

 motion in the shape of a rigor. This may be immediately followed by complete 

 suppression of secretion by the kidneys ; and if this does not pretty soon pass 

 off it is fatal. Such was the case with the patient to whom I am referring. 

 In spite of hot applications to the skin — which sometimes work like a charm 

 in such circumstances, operating, as it would appear, by distracting, so to speak, 

 the attention of the nervous system from the affected organs — that man died 

 within a few hours of the rigor. On post mortem examination the kidneys 

 presented on section an appearance that I have never forgotten ; scarlet redness 

 throughout what in other respects appeared to be perfectly sound structure. 



The previous healthiness of the patient seems to preclude the idea that 

 this grave disorder of the kidneys could have existed before the rigor. We 

 are therefore led to believe that the prostration of vital energy which inflam- 

 matory congestion implies was caused by the irritation in the urethra. If 

 such was the case, the remoteness of the kidneys from the source of disturbance 

 makes it certain that the disorder was brought about through the nervous 

 system. This effect could not possibly be produced, like arterial relaxation, 

 by failure of the nerves to act. For we know that the tissues retain their vital 



