74 Dr. Wilson Philip 



sensorium, of exciting the muscular fibre, of separating and re- 

 combining the elementary parts of the blood in the formation of 

 the secreted fluids, and of causing an evolution of caloric from 

 the blood. 



That the nervous influence is the means of conveying im- 

 pressions to, and from, the sensorium, will not be denied. 



That it acts merely as a stimulus, without bestowing any 

 power on the muscular fibre, appears from the thirty-second ex- 

 periment of the above-mentioned Inquiry, which shews, that an 

 artificial stimulus more quickly exhausts the excitability of this 

 fibre, when it is exposed at the same time to the operation of the 

 nervous influence, than when it is exposed to the effects of the 

 artificial stimulus alone. 



That the nervous influence is an agent in the formation of the 

 secreted fluids, we learn from experiments which shew that when 

 this influence is withdrawn from the lungs and stomach, these 

 organs in all other respects remaining in the same state, their 

 secretions are deranged. Fluids, indeed, are still deposited in 

 their cavities, and apparently as copiously as before ; but these.-^ 

 fluids no longer undergo the proper change. Those of the lungs y 

 assume an appearance differing little from that of the sanious 

 discharge from some kinds of wounds. The fluids of the sto- 

 mach, we know, are no less altered, because they no longer make 

 any impression on the food. These facts do not rest on the ac- 

 curacy of my experiments alone, as many of my opponents seem 

 to imagine. They were long ago pointed out, as stated in the 

 above Inquiry, by the experiments of Haller, and other Physio- 

 logists of the first name. I only add my testimony to theirs in 

 proof of them *. It appears, then, that the nervous influence is 

 necessary to the function of secretion. It either bestows on the 

 vessels the power of decomposing and recombining the elementary 

 parts of the blood, or effects those changes by its direct operation 

 on this fluid. From many facts stated or referred to in my In- 



* My Inquiry into the Laws of the Vital Functions, Exper. 44, 45. See 

 also Exper. 54, 55, 56', 57, 58. The page and number of the experiment 

 referred to in the following paper are those of the second edition of the 

 Inquiry, , 



