June 27, 1913] 



SCIENCE 



971 



meability and henee interfere with stimula- 

 tion. The osmotic motor mechanisms of 

 plants, whose action depends on sudden in- 

 crease of permeability, may in fact readily 

 be rendered irresponsive by anesthetics, as 

 Claude Bernard pointed out long ago in his 

 classical lectures on the life-phenomena 

 common to animals and plants. Or the ex- 

 planation may be somewhat different. The 

 anesthetic may leave the resting permeabil- 

 ity of the membrane the same as before — 

 or perhaps may change it in either direc- 

 tion — but alter its properties so as to de- 

 crease the readiness with which the perme- 

 ability is changed by other agencies acting 

 on the membrane. Changes of condition, 

 electrical or otherwise, that normally act 

 as stimuli would then no longer affect the 

 membrane, and wovild hence cease to stim- 

 ulate. But whatever general interpretation 

 we adopt, it is demonstrable that the prop- 

 erties of the membranes are. altered during 

 anesthesia in such a way as to make in- 

 crease of permeability more difficult than 

 in the normal sensitive state of the irritable 

 tissue. 



Is this the whole explanation of the anti- 

 stimulating action of anesthetics? Noth- 

 ing but further experimentation can answer 

 such a question. Suppression of stimula- 

 tion is however the essential effect to be ex- 

 plained. It must be remembered that any 

 specific response to stimulation comprises a 

 series of mutually interdependent proc- 

 esses, beginning with the one caused di- 

 rectly by the external agent, and ending 

 with the special physiological activity, or 

 response, characteristic of the tissue. It 

 seems more liliely that the anesthetic inter- 

 feres with the initial process of such a 

 series than with one occurring later — such 

 as the increase in oxidation or other special 

 effect. The evidence which I have cited 

 indicates in fact that the primary process 

 in stimulation is a membrcme-process, and 



that it is this process which is modified by 

 the anesthetic. This is why the succeeding 

 and outwardly more evident effects of stim- 

 ulation are also modified in the way that we 

 observe. 



It is well known that an influential group 

 of physiologists, headed by Verworn, main- 

 tain that a suppression or prevention of 

 oxidation-processes is the essential basis of 

 anesthesia. Various facts are adduced in 

 support of this theory. During anesthesia 

 the oxidative metabolism of the tissue is di- 

 minished. This fact in itself is equivocal; 

 stimulation causes increased oxidations in 

 many tissues, and suppression of stimula- 

 tion prevents this effect along with the 

 others. Lack of oxygen arrests many 

 physiological activities that are dependent 

 on its presence, but this fact again does not 

 justify Verworn 's identification of narcosis 

 and asphyxia. Other facts seem more con- 

 sistent with this view. Frohlich and 

 Heaton find that the recovery of nerves 

 from anesthesia is imperfect or delayed in 

 absence of oxygen ; Isliikawa, another pupil 

 of Verworn 's, finds the same for AmcebEe ; 

 from which they conclude that suppression 

 of oxidations is the essential feature of the 

 condition. These observations merely show 

 once more that the cell or tissue requires 

 oxygen in order to exhibit its normal prop- 

 erties. Mansfeld finds that the concentra- 

 tion of anesthetic required to anesthetize 

 tadpoles is less when oxygen is deficient 

 than when it is abundant; i. e., anesthesia 

 and asphyxia show additive relations to 

 each other. This again is equivocal. The 

 action of nerve-cells is intimately depend- 

 ent on a good supply of oxygen ; when oxy- 

 gen is deficient their excitability is lowered, 

 and along with this the degree of anesthesia 

 required to abolish excitability. Other 

 parallels of similar nature seem open to ob- 

 jections of the same kind. On the other 

 hand, nerve trunks resist the lack of oxy- 



