Physics in Medicine 5 



medical men have not shown the greatest interest in the use of 

 physical techniques. The significant development of the present 

 day is rather the emergence of a group of physicists employed 

 solely in the study and control of physical agents in their applica- 

 tions to medicine, and in the recognition that the physicist is now 

 an indispensable member of any team of specialists using X-rays 

 or radium in the treatment of malignant diseases, and generally 

 in the therapeutic use of ionizing radiations. In this development 

 Britain has played a notable part, and it is probably true to say 

 that the importance of the physical aspects of medical radiology 

 are as well recognized here as anywhere in the world. 



It is to be hoped that similar development of physical medicine 

 may occur in the near future, for the crying need in this branch 

 of medicine is for quantitative information, a great deal of which 

 can be obtained only by exact physical experiment. It is a curious 

 thing that the use of heat, one of the oldest medicaments, is from 

 the physical point of view almost entirely unscientific, and that 

 only recently have measurements in absolute units been linked 

 to clinical practice. 



It is natural that we find the medical man, a member of one 

 of the few educated sections of the community, among the first 

 to make a contribution to "pure" physics. As late as 1600 we 

 have Gilbert of Colchester, physician to Queen Elizabeth, becom- 

 ing the father of electrical science, or Borelli seeing in the move- 

 ments of man and animals applications of the laws of levers. 

 Even in the beginnings of the modern epoch we find many physi- 

 cians and surgeons contributing vitally to pure physics. 



Thomas Young perhaps stands out as the physician who, in 

 the early years of the nineteenth century, did most to transform 

 physics into its present shape. Mayer, the tragic German physi- 

 cian, so stoutly championed by Tyndall as one of the discoverers 

 of the great generalization of Conservation of Energy, on the 

 basis, be it noted, of observations of the blood of the Javanese, 

 is a notable medical contributor to physics. Tyndall himself, 

 through his researches in the domain of radiant energy, as well 

 as his intervention in the controversies around spontaneous gen- 

 eration and the bacterial origin of disease, is one of the greatest 



