ON THE PHYSIOLOGICAL ACTION OF CERTAIN AMYL COMPOUNDS. 279 



the muscular irritability of the heart is retained in some cases for so long a 

 period as eighteen hours; hence I think it follows conclusively that the 

 influence of the poison is exerted mainly on the nervous centres, and that the 

 stimulus to muscular action or the tension of force derived from those" centres 

 is simply reduced or withdrawn. I conceive also it is another fair inference 

 to suppose that the compounds exert their influence first on those portions 

 of the nervous organism from which the motor power, as apart from the sen- 

 sory and conscious, is derived. 



Before closing this descriptive section of my report, I would add that, in 

 the experiments to which attention has been drawn, dogs, rabbits, and guinea- 

 pigs were the animals subjected to observation. To make the experiments 

 strictly fair, to forbid any suspicion to the effect that the differences or even 

 the analogies observed were due to peculiarities of the animals, one animal, 

 a strong guineapig, was subjected at intervals of ten days to the extreme 

 action, short of actual death, of the various compounds submitted to exami- 

 nation. 



Practical Conclusions. 



It remains for me now, in a few short paragraphs, to sum up the lessons 

 which are taught by these experiences. 



I. — In the first place, something is added to our knowledge of therapeutics 

 or rational principles of remedies. This is hardly perhaps the place to descant 

 on special remedies for the treatment of disease, and I shall forbear on this 

 point ; but I may state generally that, according to present knowledge, none 

 of the amyl-compounds can be said to replace either ether or chloroform as 

 anaesthetics : amylene, the best of the series, is known not to be free of 

 danger, and it is less manageable than chloroform without being devoid of any 

 of the objections of chloroform, except the one, that it does not so often 

 produce vomiting. This advantage, though most important, is after all insuf- 

 ficient as a single favourable recommendation. 



But there is one direction towards which our minds cannot fail to be di- 

 rected, and following which we may expect useful results in a therapeutical 

 inquiry, — I refer to the application of these substances as remedies in certain 

 convulsive and spasmodic diseases, in which the symptoms are obviously in- 

 duced by morbid sensibility or excitability of the motor tracts and centres of 

 the nervous system. "When we know that in these agents we possess reme- 

 dies which produce lessened action of the motor force resident in nervous 

 matter, but which at the same time affect the consciousness in a secondary- 

 degree only, and do not affect the muscular irratibility at all, we cannot but 

 be impressed with the feeling that they would largely control the nervous 

 excitation in cases where that is dangerously and fatally called forth. I 

 refer more particularly to cases of tetanus or locked jaw. Here I think it 

 would be rational to bring these agents into requisition as remedies, and 

 comparing the agents one by one, and after studying carefully their effects, I 

 should conclude that the iodide of amyl would on the whole be most pro- 

 mising. It has the advantge of being readily administered by inhalation ; 

 it produces less muscular excitement than the nitrite, and it is, I believe, 

 chemically a safer preparation ; it does not so determinately check oxidation 

 as the rest ; it promotes secretion ; it is more permanent in its effects than 

 amylene, and it is less persistent than either the acetate or the amylic alcohol. 

 In a case of hopeless tetanus I should have no hesitation in administering 

 iodide of amyl until decided reduction of nervous excitability was indicated, 



