ON THE PHYSIOLOGICAL ACTION OF CERTAIN AMYL COMPOTJNDS. 275 



certain proceedings upon winch it was predetermined. We have a similar 

 phenomenon to this in our daily range of experience, in the fact that we can 

 under pressure go to sleep determining that we will wake at a certain time, 

 and do so almost to the minute. In both these cases it seems as though 

 the dark sleep were pierced by one pervading conscious gleam of light 

 which obeys the orders it has received, and watching the slumbering spirits 

 around it, calls them forth into activity at the proper time, and then itself 

 dies away. 



The insensibility produced by amylene is very complete but exceedingly 

 transient ; recovery after the vapour is withdrawn is sudden, and it is 

 therefore necessary to keep up the effect by constant inhalation of large 

 quantities of the vapour. Between the period of full sensibility and com- 

 plete insensibility there are three well-marked stages. The first is one of 

 mild excitement, during which the face becomes red and injected; then a 

 period of staggering inebriation ; and thirdly, a period of collapse and insen- 

 sibility. Snow added a fourth stage of entire muscular relaxation, but I 

 have myself not been able to follow it. During narcotism from this agent there 

 is no convulsion, but not unfrequently there is a peculiar tremor of the muscles 

 very general, but, if I may use the term, minute. Carried to an extreme, 

 the vapour kills animals. The only structural peculiarity found after death, 

 is engorgement of the right side of the heart. The lungs are healthy, and 

 the blood is unchanged in its general physical properties. I would dwell 

 on this last fact with emphasis in order to correct an error made by the 

 reporter on amylene to the Academy of Medicine of Paris, to the effect that 

 amylene removed the red colour from arterial blood, whereas chloroform does 

 not. This is a mistake, founded obviously on an inference derived from imper- 

 fect observation. When amylene is added in quantity to arterial blood drawn 

 from the body, it does unquestionably produce darkness of coloiir ; but in the 

 living animal, during its exhibition by inhalation, no such event occurs ; for 

 I have taken the blood from artery and vein, and have compared the specimens. 

 The colour of both bloods is normal, the period of coagulation is natural, and 

 the corpuscles are unchanged. 



Owing to the fact that amylene is feebly soluble in water, and therefore 

 feebly soluble in serum of blood, a very large percentage of it requires to be 

 inhaled before any effect is produced. Snow estimated that the air must be 

 charged with 40 per cent, in order to produce entire insensibility, and in 

 fact he under- estimated the quantity by working on water at a temperature 

 of 56° instead of 96° Fahr. I find that, instead of 40, 50 per cent, of the 

 vapour actually is required. But as the blood at its ordinary temperature 

 can only absorb ju-jjy-g-th part of the vapour of amylene, it cannot, even in 

 an adult man, receive at any time more than from 4| to 5 grains. It is 

 clear, too, from the rapidity with which recovery takes place, that the fluids 

 of the tissues receive but feeble impregnation. 



In order to institute a physiological comparison, I tried the effect of the 

 analogue of amylene defiant gas. Olefiant gas is the hydruret of acetyle, 

 but, like amylene, it is a pure hydrocarbon ; its composition is different only 

 in one respect, viz. that it is composed of four equivalents of carbon and 

 four of hydrogen. As I had anticipated, the action was nearly the same ; 

 to produce perfect insensibility, 50 per cent, of the gas was required in inha- 

 lation. The effects also were transient. 



The effect of amylene on the muscular tissue was studied in various 

 ways. As will already have been gathered, it reduces the muscular power, 

 but the effect is not abiding. In fact amylene approaches the class of 



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