December 2ti, 19lid.] 



SCIENCE. 



1013 



•the physician. As a possible instance of 

 this may be mentioned the idea, recently 

 suggested by Professor Herter, of New 

 York, that the suprarenal gland, by means 

 of its internal secretion may control the 

 manufacture of sugar by the cells of the 

 pancreas, an idea which, if proved true, 

 may bear significantly on the causation and 

 treatment of diabetes. There is need of 

 much research in this field of the internal 

 secretions, but already glandular extracts 

 have proved a valuable addition to the 

 remedies of the scientific physician. 



Brain Surgery. — I have already spoken 

 of the entire change in the methods of 

 general surgery during a period of twenty- 

 five years, owing to the rise of bacteriology. 

 But I ought to mention specifically the re- 

 markable advance made during the same 

 time in the surgical treatment of diseases 

 of the central nervous system, the brain 

 and the spinal cord, for it is here that the 

 scientific method has achieved one of its 

 most complete triumphs. 



Although it was pointed out by the 

 French surgeon, Broca, as early as 1861, 

 that the loss of the power of speech is 

 associated with disease of a certain portion 

 of the left hemisphere of the brain, it was 

 still the general belief that the acting brain 

 acts as a whole. This idea prevailed until 

 1870, when the German physiologists, 

 Fritsch and Hitzig, demonstrated that 

 stimulation of different areas of the cer- 

 ebral surface evoke in the body different 

 movements. This was the beginning of 

 the experimental investigation of cerebral 

 localization, a line of research which has 

 proved rich in results. The brain is not 

 one organ acting as a whole, but an asso- 

 ciation of many organs, each with its spe- 

 cific duty to perform, but intricately asso- 

 ciated with all the others. In the years 

 that have passed since the discovery of 

 Pritsch and Hitzig it has been the task of 

 neurologists to discover the functions of 



the different parts of the central nervoua 

 system, to unravel their intricate intercon- 

 nections, and to associate the disturbance 

 of their, functions with external symptoms 

 in the individual. As a result of this labor 

 the neurologist, after a careful study of his 

 patient, now says to the surgeon, 'Cut 

 there, and you will find the disturbing 

 agent'— and the brilliant success of the 

 brain surgery of the present day justifies 

 its scientific basis. 



The New Physical Chemistry. —In. the 

 early part of this address I spoke of the 

 freedom with which medicine made use of 

 discoveries in other sciences than its own. 

 A very recent striking illustration of this 

 is that of the application of the principles 

 of the new physical chemistry to the phe- 

 nomena of the living body. From the 

 standpoint of physical chemistry the body 

 may be regarded as a mass of minute par- 

 ticles of semi-liquid living substance, the 

 protoplasmic cells, each surrounded by a 

 thin permeable membrane, the cell-wall, 

 and bathed externally by the circulating 

 liquids, the blood and lymph. Both the 

 protoplasm and the external liquid con- 

 tain substances in solution, and whatever 

 passes between them, be it food, or waste, 

 or drug, must pass in the form of a solu- 

 tion through the intervening cell- wall. The 

 laws of solutions and the laws of the pas- 

 sage of solutions throi^gh membranes must 

 hence find their applications in the body. 

 It has been the general belief that when a 

 substance becomes dissolved its molecules 

 remain intact, and are merely separated 

 from one another by the water or other 

 solvent. Quite recently physical chem- 

 istry has shown that this view is not alto- 

 gether correct, but that a varying amount 

 of disintegration takes place, a dissocia- 

 tion of the molecules into their constituent 

 atoms or groups of atoms. Moreover, these 

 dissociated particles, ions, as they have been 

 called, are charged with electricity; some. 



