480 MUSCLES, 



more if the brain and spinal chord are entire, than if they are 

 previously removed : and the inference is clear, that the nerves 

 more readily transmit the effects of the poison than other parts, and 

 not that the muscles lose their excitability through the loss of the 

 nervous influence ; because the destruction of the brain and spinal 

 chord has not the effect of poison. Another fact of the same 

 kind is the immediate cessation of the action of the heart or of 

 the intestines by the injection of poison into their cavities, while 

 its application to their external surface operates slowly upon 

 them. h Far greater nervous connection must exist between their 

 inner surface than their outer surface and their muscular fibres, 

 because these are destined for stimulation by their contents, and 

 not by matters on the exterior ; and thus the effects of poisons 

 will be more readily transmitted by the inner than the outer 

 surface, just like the effects of all stimulating causes. Detached 

 muscles contract under the application of various stimuli of 

 all kinds, and this looks as if their power of contraction is 

 their own. When a detached muscle can be excited no longer, 

 a little rest enables it to become excitable again : and the 

 alternations may be repeated many times. Nay, if a muscle is 

 not detached, but merely all its nerves divided so that its life is 

 preserved, its excitability may be exhausted and recovered for 

 some days. 1 The power continues longer after separation in cold 

 than in warm blooded animals ; in voluntary muscles than in the 

 involuntary ; and Dr. Whytt discovered, also, that, when an 



g Whytt himself infers that " opium does not only destroy the moving power 

 of the muscles of animals, by intercepting the influence of the brain and spinal 

 marrow, but also by unfitting the muscular fibres themselves, or the nervous 

 power lodged in them, for performing its office." " It destroys their powers, by 

 means of that sympathy which they have through the brain or spinal marrow, 

 with the nerves to which the opium is immediately applied." Experiments made 

 with Optuyn on living and dying Animals. First published in Ed. Physical and 

 Literary Essays. 1755. (r.) 



I may remark that he found the nearest part of the nervous system to be the 

 most affected ; for, when a solution of opium was inserted into the large in- 

 testines, " dogs not only lost the power of motion sooner in their hinder legs 

 than in their fore ones, but also were insensible of any pain in them, and yet 

 howled strongly when their ears were pinched." (m.) 



h Dr. Munro Secundus, and Dr. Wilson Philip ; confirmed by Dr. C. Henry, 

 1. c. Still Whytt found opium to poison the whole system sooner if injected 

 Into the peritonaeum than into the stomach or rectum. 1. c. Exp. 21, 22, 23. 



1 Report of the Fourth Meeting of the British Association. 1835. p. 671. sqq. 



