SLEEP 151 



drug disappears from the circulation. . . . The pseudo- 

 degenerative change produced by the chemical action of 

 the anaesthetic no doubt interferes with the normal meta- 

 bolic activity of the cell-body, and this produces effects 

 upon the cell-branches." 



From an electro-physiological point of view the normal 

 metabolic activity of the cell-body would be interfered with 

 if the electrostatic capacity of the cell was interfered with 

 and we have the undoubted fact that anaesthetics such as 

 chloroform and ether largely increase the resistance of the 

 nerve substance or alternatively, lower the electrostatic 

 capacity of cell-bodies. 



" The theory which has met with most favour in relation 

 to anaesthetics, however, is that known as the Meyer-Overton 

 hypothesis ; this theory, which has received abundant 

 confirmation by numerous observers, points out that the 

 cells are easily permeable to the volatile anaesthetics owing 

 to the presence of fat and lipoid material in their plasmatic 

 membrane. It can hardly now be doubted that the solubility 

 of the volatile anaesthetics in the lipoids of the membrane 

 (or what comes to the same thing, the solubility of the 

 lipoids in the anaesthetic) is an important factor in anaes- 

 thesia ; the anaesthetic thus enters the cell easily, and 

 throws the lipoid constituents of the protoplasm . . . 

 out of gear, the net result being a lessening of the oxidatine 

 changes which are essential in active vital processes." 



In other words lessening of intra-cellular neuro-electrical 

 generation and transmission. 



" But," as Halliburton remarks, " the artificial sleep 

 of a deeply-narcotised animal is no criterion of what occurs 

 during normal sleep. The sleep of anaesthesia is a patho- 

 logical condition due to the action of a poison. The drug 

 reduces the chemico- vital activities of the cells, and is, 

 in a sense, dependent on an increasing condition of exhaus- 

 tion, which may culminate in death. Natural sleep, on the 

 other hand, is the normal manifestation of one stage in the 

 rhythmical activity of nerve-cells, and though it may be 

 preceded by fatigue or exhaustion, it is accompanied by 

 repair, the constructive side of metabolic activity. This 



