many other researchers, the ability of medicine to control 

 the majority of infectious and contagious diseases through 

 preventive immunization, and chemical or physical de- 

 struction of bacteria outside the body, was greatly increased. 

 The exact manner of transmission of the different disease 

 bacteria was determined, and their resistance to antisep- 

 tics and disinfectants was measured. The discovery of the 

 first drugs capable of attacking bacteria within the body, 

 (e.g. salvarsan for syphilis, Ehrlich, 1910), and then of 

 the general antibiotics, (penicillin, Fleming, 1929; sulpha 

 drugs, tetramycin, etc.), virtually conquered the stubborn 

 staphylocci and streptococci which cause boils, throat in- 

 fections, etc., and the pneumococci causing pneumonia, and 

 made practicable the treatment of tuberculosis. 



Almost immediately after the discovery of X-rays by 

 Rontgen (1895), these body-penetrating rays were used 

 to produce shadowgraphs revealing the exact nature of 

 bone fractures and the location of metal objects accident- 

 ally imbedded in the body. With the use of X-radiation 

 opaque substances introduced in solution into various body 

 organs (heart, stomach, intestine, kidney, etc.). the sites 

 of any defects in such organs could be delineated prior to 

 operation, leading to increased success in treatment. More 

 lately, the use of radioactive isotopes introduced into the 

 body, has led to even greater diagnostic ability: e.g. in 

 locating brain tumours, in measuring lung efficiency, and 

 in determining blood circulation. 



The surgeon is nowadays able, through the develop- 

 ment of such apparatus as the heart-lung machine, the arti- 

 ficial kidney, new surgical instruments (e.g. the blood 

 vessel stapler), the electroencephalograph for examining 

 abnormalities in brain function, the cardiograph, surgical 

 cryogenics (freezing of organs to slow metabolism), etc., to 



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