162 HUMAN BIOLOGY 



however, he may still be able to ride (on horseback), and a man who 

 is so drunk that he cannot walk and cannot speak may ride perfectly 

 well. . . . Later on the further anaesthetic action of the alcohol 

 abolishes sensation, and its paralyzing action destroys the power of 

 the spinal cord, so that the man is no longer able even to ride ; but 

 still the respiratory center in the medulla will go on acting, and it is 

 not until enormous doses of alcohol have been given that respiration 

 becomes paralyzed. 



" Alcohol . . . makes all the nervous processes slower, but at the 

 same time it has the curious effect of producing a kind of mental 

 anaesthesia, ... so that these processes seem to the person himself 

 to be all quicker than usual, instead of being, as they really are, much 

 slower. Thus a man, while doing things much more slowly than 

 before, is under the impression that he is doing things very much 

 more quickly. What applies to these very simple processes applies 

 also to the higher processes of the mind ; and a celebrated author 

 once told me that if he wrote under the influence of a small quantity 

 of alcohol, he seemed to himself to write very fluently and to write 

 very well, but when he came to examine what he had written next 

 day, after the effect of the alcohol had passed off, he found that it 

 would not stand criticism." 1 



V. THE EYES 



243. Protection for the eye. The delicate organs of vision, the 

 eyes, are protected in a wonderful manner. In the first place, the 

 eyeballs are set far back in bony sockets, in such a way that, even 

 if one falls forward or if the face is struck with a large object, there is 

 little danger that the eyes themselves will be hit. Again, each eye- 

 ball is covered by two movable lids that involuntarily close at any 

 threatened danger. And, finally, the curving eyelashes on the edge 

 of each lid protect the eyeball to a considerable extent from dust 

 and dirt. 



244. Structure of the , eye. Each eye is nearly spherical in 

 shape (Fig. 52) . Its outer surface is covered with a tough coat which 



1 T. Lauder Brunton, London, "Lectures on the Action of Medi- 

 cine," pp. 190, 191, 194. 



