RESEARCHES ON CHLOROFORM ANAESTHESIA 637 



at certain vapour pressures, a fact which is not easy to deter- 

 mine except at high pressures. Conversely, the absorption 

 of chloroform by saline does, as might be expected, follow 

 the law of absorption for varying pressures, and when the 

 results are plotted out the curve is a straight line. At a 

 temperature of 40 C, and at the anaesthetising value of 

 8-10 mm. of mercury, the coefficient of distribution between 

 vapour-space and solvent for haemoglobin is about yi, and at 

 a room temperature of about 15 C. this would be 18. 



Additional experiments performed by Moore and Roaf 

 render the views of Overton and Hans Meyer, which have 

 obtained such wide credence, somewhat improbable. At equal 

 concentration of chloroform in water and saline the vapour 

 pressure of the drug always exceeds what is found for haemo- 

 globin or the protoplasmic cells of the heart, brain, or muscle ; 

 in other words, the association of the anaesthetic with proteins 

 lowers the vapour pressure, just as the tension of oxygen in 

 the blood is low, owing to its association with haemoglobin. 

 The theory which ascribes the action of general anaesthetics 

 to a relationship which becomes established between the lipoids 

 (substances of the cell soluble in ether, such as lecithin and 

 cholesterin) does not conform with the experimental fact that 

 ethereal emulsions of the brain, which organ is considered 

 to be so specifically affected by chloroform, behave exactly 

 like water or saline solutions ; in other words, obey the Dalton- 

 Henry law as far as chloroform vapour is concerned, while 

 emulsions of the entire brain, cells and lipoids show that this 

 law is no longer followed, but that there is undoubted asso- 

 ciation of the anaesthetic at high vapour pressures. Further, 

 comparative determinations of vapour pressure and concen- 

 tration of chloroform vapour leave no doubt but that it is 

 the proteid constituent, and not the lipoid material, which is 

 responsible for the actual physical aggregation or chemical 

 combination which takes place. Far from the anaesthetic 

 state being 'due to an affinity of the lipoids of the cells for an 

 anaesthetic, the existence of such substances in bulk, as 

 is the case for individuals who possess a large quantity 

 of fat, actually imprisons a quantity of the anaesthetic which 

 is given, so that it is no longer available for poisoning the 

 cells of the organism, which is essential if anaesthesia is to 

 occur, for it is well known to anaesthetists that the greater 



4i 



