1818.] Dr. Philip on Stimulants and Sedatives. 375 



first impression on the living solid, those best calculated to pro- 

 duce excitement should be found capable of the greatest sedative 

 effect. But this is so far from being true, that we find that the 

 agents which produce the greatest degree of this effect are the 

 worst stimuli. Tobacco, for example, which is one of the most 

 powerful sedatives, cannot, by any management, be made to 

 produce the degree of excitement which arises from opium or 

 distilled spirits. . 



The sedative, like the stimulant effect, may be communicated . 

 to the muscular through the nervous system. When tobacco is 

 applied to any considerable part either of the brain or spinal 

 marrow, as I have ascertained by repeated experiment, the heart 

 soon begins to act more languidly ; but this languor is preceded 

 by little, if any, increased action, unless the tobacco be applied 

 in a very diluted state ; in which case, it produces comparatively 

 little languor, and the excitement is much less than that pro- 

 duced bv opium, which is followed by no sensible languor. 



If we "disregard preconceived opinions and fix our attention 

 on facts alone, we shall, as far as I am capable of judging, 

 arrive at the following conclusions. Every agent capable of 

 affecting the living solid acts both as a stimulus and sedative 

 according to the degree in which it is applied. Applied within 

 certain limits, it is a stimulus ; and in proportion as it stimulates, 

 it exhausts the excitability, this being equally true of the inter- 

 rupted excitement which stimuli produce in the muscular, as of 

 the permanent excitement which they produce in the nervous 

 system. Applied beyond these limits, agents no longer produce 

 excitement followed by proportional exhaustion, but direct 

 exhaustion arising from the operation of the agent, and wholly 

 unconnected with previous excitement, the stimulant and seda- 

 tive powers existing in no particular proportion to each other, 

 but in different agents in every possible proportion. I have j as 

 had occasion to mention the comparative effects of tobacco and 

 opium in the heart. Thus the stimulant power of distilled spirits 

 is great, its sedative power small. It must be used in very great 

 quantity to produce the sedative effect ; while a small quantity 

 of digitalis produces this effect, and its stimulant power is very 

 slight. 



These observations apply to agents affecting the mind as welt 

 as the body. Grief and fear possess great sedative power ; they 

 act as stimulants only when they are present in a comparatively 

 small degree. Joy and anger, on the other hand, are powerful 

 stimuli, and only act as sedatives when in excess. There is no 

 exception, I believe, to the law we are considering. There is 

 no agent which may not be made to produce a stimulant effect 

 by applying it in very small quantity, and none which does not 

 act as a sedative when applied in excess. I remain, dear Sir, 



Your faithful humble servant, 



A. P. W. Philip. 



