214 INTERNAL MEDICINE 



of resistance of the economy against infection, has given us, with 

 the discovery of specific agglutinines and precipitines, diagnostic 

 methods of the greatest value, not only for the recognition of vari- 

 ous infectious processes, but for the identification of specific sera, 

 affording in particular a test for human blood destined (probably) 

 to prove, when properly applied and interpreted, of great medico- 

 legal value. 



This is indeed a gain over our knowledge of one hundred years 

 ago. In how many fields has the conjectural given way to the exact! 

 At the end of the eighteenth century the diagnostic effort of the 

 physician, unaided by instruments of precision or even by the 

 simplest physical methods of auscultation and percussion, was 

 directed toward the detection of gross anatomical changes. To- 

 day with our increased knowledge of anatomical, physiological, 

 and pathological processes, with our growing insight into the chem- 

 ical and physical features of vital activity, our duty no longer ends 

 in the recognition of physical changes in organs, in the determina- 

 tion of the presence of a specific lesion or infection; it is further 

 our task to search for the earliest evidence of disturbance of func- 

 tion, which may later lead to grosser, more evident change, to 

 separate the physiological from the pathological, to estimate, as 

 far as may be, the power of resistance of the different organs and 

 tissues and fluids of the body to insults of varying nature, to de- 

 termine the functional capacity of a given organ its sufficiency 

 or insufficiency. In addition to increasing opportunities in the 

 field of pathological anatomy we find ourselves drawn further into 

 the study of pathological physiology and knowledge in the field 

 of pathological physiology leads of necessity to power in functional 

 diagnosis. 



It must be acknowledged that with regard to many organs the 

 determination of the limits of functional power and the estimation 

 of the degree of impairment in disease are matters most difficult 

 to appreciate, yet with improved methods and persistent research, 

 progress is being made. 



We are, after all, but beginning to realize a few of the possibil- 

 ities before us, but even this is a step in advance which holds out 

 no little promise for the future and offers new and tempting oppor- 

 tunities for study and investigation. 



At the end of the eighteenth century but three important, ra- 

 tionally conceived measures of prophylaxis had been practiced 

 the dietetic measures of protection from scurvy, the older inocu- 

 lation and Jenner's great contribution of vaccination against small- 

 pox. It was not, indeed, until the development of bacteriology 

 that prophylaxis took its place as a scientifically exact branch of 

 medicine. The recognition of the specific cause of many infectious 



