CH. XLVIII.] SLEEP AND NAKCOSIS 701 



enlargements are therefore not the primary cause of loss of conscious- 

 ness, but are merely secondary results of changes in the cell-body. 

 When a tree begins to wither the earliest apparent change is noticed 

 in the branches most remote from the centre of nutrition, the root ; 

 as the changes in the centre of nutrition become more profound, the 

 larger branches become implicated, but the seat of the mischief is 

 not primarily in the branches. This illustration may serve to render 

 intelligible what is found in n^rve-cells and their branches. 



Whether the appearances found in dogs and rabbits are appli- 

 cable to the human subject is another question. I am inclined to 

 think that we may safely regard them as such ; there is no reason 

 why an anaesthetic should act differently in different animals. The 

 resistance of the animal is a variable factor, and this causes a varia- 

 tion in degree only ; the effect is probably the same in kind for all 

 animals, man included. 



But I feel that we should be very chary in concluding that the 

 artificial sleep of a deeply-narcotised animal is any criterion of what 

 occurs during normal sleep. The sleep of anaesthesia is a pathologi- 

 cal 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 exhaustion, which may culminate in death. 

 Normal sleep, on the other hand, is not produced by a poison, or at 

 any rate we have no evidence of any poison ; it is the normal mani- 

 festation of one stage in the rhythmical activity of nerve-cells, and 

 though it may be preceded by fatigue or exhaustion, it is accom- 

 panied by repair, the constructive side of metabolic activity. 



Loss of sleep is more damaging than starvation. Dogs will recover after being 

 starved for three weeks, but they die from loss of sleep in five days. The body 

 temperature falls, reflexes disappear, and post-mortem the brain is found to contain 

 capillary haemorrhages, the cord is dry and anaemic, and fatty degeneration is found 

 in most of the tissues. 



In man, loss of sleep curiously enough oauses a slight rise in weight ; the body 

 temperature falls ; the excretion of nitrogen and still more so that of phosphoric acid 

 increases ; the reactions of the muscular, and later those of the nervous, system 

 diminish in intensity, except that in all cases there is an increase in acuteness of 

 vision. These experiments were made by Patrick and Gilbert on three young men, 

 who voluntarily went without sleep for ninety hours. At the end of the experiment 

 a very small extra amount of sleep beyond the normal caused complete restoration, 

 and all the symptoms, including the increase of weight, disappeared. 



