RECENT PROGRESS 249 



development of the body and to some of its 

 functions. 



It is impossible to stop and appraise the effect 

 upon medical thought and practice of the kind of 

 knowledge which has been illustrated by these 

 brief and very inadequate references. It is enough 

 to point out at how great a relative disadvantage 

 was the doctor when he had to minister to the body 

 in ignorance of such things. Yet he was well 

 nigh wholly ignorant of them a few years ago. 

 Our present detailed knowledge of the central 

 nervous system ; of the localisation of function on 

 the surface of the brain ; of the significance of 

 certain types of nerve cells and their processes; 

 of the intricate course of the nerve tracts which 

 carry this or that particular impulse, and such 

 understanding as we may have of the nerve impulse 

 itself, have arisen largely from experimental research. 

 Although observations, made upon man, of the 

 symptoms which follow upon injuries and disease 

 occurring in known localities of the nervous system 

 (observations which during a great war are only 

 too frequent) have taught us much in this direction, 

 it is only by abundant animal experiments that 

 such knowledge can be systematised and consoli- 

 dated. 



Physiology is beginning to explain the true 

 inwardness of diseases of metabolism of gout, 

 diabetes, and the like; and, by experiment, is 

 learning much for the future service of medicine 



