708 



SCIENCE. 



[N. S. Vol. XX. No. 517. 



with Skoda and Schonlein in Germany and 

 Addison and Bright and Stokes in Eng- 

 land, the exact association of clinical pic- 

 tures with local anatomical changes made 

 great advances. Typhus and typhoid 

 fevers were distinguished; the relation be- 

 tween albuminuria and renal disease was 

 demonstrated; the association of endo- 

 carditis with acute rheumatism was dis- 

 covered ; the corner-stone of our knowledge 

 of cerebral localization was laid. Clinical 

 diagnosis was becoming more than a con- 

 jectural art. 



In the meantime physiology was making 

 great strides. Majendie, Bell, Johannes 

 Miiller, Beaumont and finally Claude Ber- 

 nard, and a host of their followers, were 

 shedding light upon many obscure corners 

 of our knowledge of the vital functions. 

 In the hands of Miiller the microscope be- 

 gan to open up new fields of study which 

 were destined in a few years, through the 

 cultivation of the genius of a Virchow and 

 a Max Schultze, to bear a noble harvest. 

 The 'great reform in medicine' which fol- 

 lowed the introduction of the cellular pa- 

 thology laid solid foundations for much 

 which is most vital in our anatomical and 

 physiological and pathological knowledge 

 of to-day, and the correlation of these ob- 

 servations with the results of accurately re- 

 corded clinical studies, the application of 

 the microscope to the study of the urine, 

 the sputa, the blood, to pathological neo- 

 plasms, to exudates and transudates, soon 

 brought new material for the rising edifice 

 of a rational, exact diagnosis. The sphyg- 

 mograph, the thermometer, the ophthalmo- 

 scope, the laryngoscope, the binaural stetho- 

 scope, the stomach tube, the various means 

 for studying the blood pressure, all have 

 brought their aid, while but yesterday the 

 discovery of Roentgen has given us new 

 and unhoped for diagnostic assistance. 



At the same time, physiological chem- 

 istry which, with the work of Berzelius on 



the urine, had taken its place by the side 

 of the more purely physical methods of in- 

 vestigation, has year by year given us 

 greater diagnostic assistance in the analysis 

 of the different secretions and excretions 

 of the body and in the explanation of the 

 various metabolic processes of the economy. 



The development in the hands of Du- 

 chenne and Erb and Remak of electrical 

 diagnosis, together with the great advances 

 in physiology and pathology of the nervous 

 system, have afforded explanation for much 

 that was previously incomprehensible and 

 have given us powers of diagnosis which, a 

 few generations ago, would have seemed 

 almost magical. 



Finally Pasteur and Koch, with the in- 

 troduction of bacteriological investigation, 

 opened the way to the discovery of the 

 causal agents of a large group of infectious 

 diseases. These discoveries, followed rapid- 

 ly by the evolution of methods allowing of 

 the clinical demonstration of many path- 

 ogenic micro-organisms, afforded an early, 

 exact and positive diagnosis, on the one 

 hand, in conditions where previously the 

 disease was recognizable only at a stage in 

 which it had made inroads into the system 

 so great as to be often beyond relief, as in 

 tuberculosis, and, on the other, in maladies 

 the existence of which, without these meth- 

 ods, was to be definitely determined only 

 after the onset of an epidemic, as in 

 cholera, plague and influenza. "When one 

 thinks of what the last quarter of a century 

 has taught us with regard to tuberculosis, 

 anthrax, tetanus, diphtheria, typhoid fever, 

 cholera, plague, dysentery, influenza, not to 

 speak of the great group of wound infec- 

 tions, we may begin to realize what bac- 

 teriological methods have done for diagnosis 

 —how many diseases have been cleared up 

 — how many symptoms have been ex- 

 plained. 



In like manner Laveran with the dis- 

 covery of the parasite of malarial fever. 



