J)r. Buchanan on the Effect* of the MafaHon of FAher. 



The most remarkable peculiarities in the action of ether administered 

 by inhalation are, 1st, the suddenness with which it induces complete 

 narcotism; 2d, the transiency of the narcotic state; and, 3d, the very 

 small quant it y of ether necessary to produce the effect. I shall endeavour 

 to show, that these peculiarities depend altogether on the mode of admin- 

 istering the ether, by inhalation; and would not be observed if it were 

 administered in any other way: and in doing this, I shall assume as 

 principles, that ether only acts as a stimulant to the heart, and as a 

 narcotic on the brain, after being absorbed ; and that the energy of its 

 action, is proportionate to the degree in which the blood applied to the 

 tissues of the heart and brain is impregnated with it. 



The suddenness of the effect produced depends, in the first place, on 

 the volatility of the ether, and on its being thus brought, at once, into 

 contact with a very extensive and highly absorbent surface — the mucous 

 membrane of the lungs. 



Another circumstance which favours much the speedy development of 

 the narcotism is, that the blood, fully charged with the absorbed ether, is 

 at once poured, undiluted, and in a continuous stream, on the heart and 

 brain. The ether is no sooner absorbed, than the blood, charged with it, 

 passes on to the cavities of the left side of the heart; and immediately 

 thereafter it circulates through the coronary vessels, and the carotid and 

 vertebral arteries, and thus pervades the tissues of both sides of the heart, 

 and every part of the brain. It is far otherwise with respect to substances 

 applied to the surface of the stomach, and absorbed by the stomachic veins ; 

 for the blood in these veins is necessarily diluted, by intermingling with 

 many currents larger than their own, before reaching the heart and brain. 

 Suppose, to take an extreme illustration, that the blood were capable of 

 absorbing as much ether as water can combine with, or one-tenth of its 

 own weight ; if, then, we suppose that the blood in the lungs were impreg- 

 nated to this extent, it would be applied in that state to the heart and 

 brain, whereas, if the blood in the stomachic veins were impregnated with 

 the same quantity of ether, before reaching the liver, it would have 

 mingled with more than its own mass of pure blood from the splenic and 

 mesenteric veins; the tenth would thus become a twentieth; and, on the 

 blood leaving the liver, and joining the larger current of inferior cava, the 

 twentieth would become a fiftieth or sixtieth. A further dilution would 

 take place at the confluence with the superior cava, so that the blood, on 

 reaching the heart and brain, instead of containing one-tenth part of 

 absorbed ether, could not contain so much as one-hundredth. Whenever, 

 therefore, the same quantity of ether, or of any other absorbible substance, 

 is taken up from the lungs and from the stomach, it must, in the former 

 case, be applied to the tissues of the heart and brain, in a state of concen- 

 tration at least ten times greater than in the latter; and will, therefore, 

 act on these organs with more suddenness and energy. 



I would explain, also, by referring to the laws which govern the circu- 

 lation of the blood, the evanescence of the effects produced, which is the 



