June 27, 1913] 



SCIENCE 



963 



of these cell-constituents it is far from 

 being a complete theory of anesthesia. 

 Such a theory would evidently involve a 

 complete theory of stimulation, and this 

 can hardly be said to exist as yet. It is, 

 however, possible, I believe, to gain further 

 insight into the nature of anesthetic action 

 by combining the results of these and simi- 

 lar experimental studies of anesthesia with 

 the results of certain more recent studies of 

 the nature and conditions of the process of 

 normal stimulation. It is necessary to 

 form some clear conception of the nature of 

 the changes involved in stimulation before 

 we can profitably consider the question of 

 just how the stimulation-process is modi- 

 fied by the presence of the anesthetic. 



Before considering in more detail the 

 mechanism of stimulation and of its modi- 

 fication by anesthetics, let us first consider 

 briefly the nature of the physico-chemical 

 constitution of the living cell, as more re- 

 cent research has led us to conceive of it. 

 This is a subject which is not easy to sum- 

 marize, and on which much light remains 

 to be thrown. It is clear, however, that the 

 living protoplasm is not a homogeneous so- 

 lution, but is a "polyphasie system"; i. e., 

 a mixture consisting of various substances 

 and solutions which are only partly mis- 

 cible with one another, and are thus inter- 

 related like the different phases of an emul- 

 sion or similar system. These several 

 phases, which are partly solid, partly 

 liquid, appear in each living cell to have a 

 constant and definite arrangement, whose 

 exact nature varies characteristically from 

 cell to cell. There appears typically to be 

 a solid or semi-solid structural substratum 

 consisting of colloidal material, most of 

 which is in a water-swollen or hydrated 

 state ; in addition to this more fixed and per- 

 manent part of the cell-organization, numer- 

 ous simpler substances are present — sugars, 

 salts, amiuo-aeids and others— largely in a 



state of simple aqueous solution, but prob- 

 ably partly adsorbed at the surfaces of the 

 colloidal phases. There is evidence that it is 

 by the oxidation of certain of these sub- 

 stances, especially sugar, rather than of the 

 colloidal material, that most of the energy 

 manifested in the cell-processes is set free. 

 The colloidal substratum furnishes the con- 

 ditions under which the energy-yielding 

 oxidations and other metabolic changes 

 take place, and apparently determines 

 their course, character and velocity. The 

 solid colloidal material of the cell may in 

 one sense be considered as by-product of the 

 metabolic activities of the protoplasm; it 

 appears, once formed, to undergo itself 

 relatively slight change, but to influence 

 profoundly, by its presence and arrange- 

 ment, the character of cell-metabolism.^ 

 The colloids are of varied chemical nature ; 

 they are chiefly proteins and lipoids, and 

 it is to be noted that they are built up by 

 various forms of molecular union and 

 polymerization from relatively simple sub- 

 stances furnished by the environment. 

 This is true not only of plants, but also of 

 the individual cells of higher animals, 

 where the material which goes to form pro- 

 teins reaches the cell in the form of amino- 

 acids, or of simple polypeptides.'' In gen- 

 eral it is from such amino-acids together 

 with salts and carbohydrates that the cell 

 builds up the colloids which form its char- 

 acteristic structural apparatus. This ap- 

 pears highly complex in some forms of irri- 

 table tissue, as in voluntary muscle; in 

 others, as in nerve, the essential structure 

 appears relatively simple. What we call 

 the "structural organization" of the cell is 

 merely another name for the physical char- 



* Cf. Child 's interesting discussion of tlie rela- 

 tion between metabolism and structure in the 

 Journal of Morphology, Vol. 22, 1911, p. 173. 



' Cf. Folin 's recent papers in the Journal of 

 Biologicol Chemistry. 



