272 INFLUENCE OF THE CIRCULATION 



is on the influx of the liquid causing the jet. It 

 should also be remembered that the nerves of the 

 part were untouched and uninjured, and that their 

 continuity with the spinal cord and brain was also 

 perfect. The most evident and simple is, conse- 

 quently, the only intelligible means of explaining 

 the phenomenon. 



The second, or pathological law, naturally follows 

 the establishment of the physiological principle now 

 stated. For, since the sensorial functions of the 

 cerebro-spinal nerves, like those of the brain itself, 

 are dependent on the normal maintenance of the 

 local circulation, it is but in accordance with the 

 general laws of disordered nervous action that an 

 excessive or defective supply of arterial blood to the 

 vessels of the part should produce corresponding 

 variations in the intensity and activity of the func- 

 tions arising from the circulation. Hence, an ex- 

 cessive supply of arterial blood produces the morbid 

 sensitiveness and pain which we so often observe to 

 accompany inflammation and determination of blood. 

 And the influence of the opposite condition in 

 diminishing nervous sensibility and the power of 

 voluntary motion, is witnessed in the partial paralysis 

 temporarily following the ligature of the secondary 

 arteries, in the stagnating influence of extreme cold 

 on the superficial capillary circulation and its conse- 

 quent benumbing effect on the adjacent nerves ; as 

 well as the sluggish movements, the diminished 

 sensibility, and the frequent tendency to local and 

 functional paralysis of the various forms of anaemia. 

 From their possession of vital endowments equal 



