2 2 THE lURTH AND GROWTH OF SCIENCE IN MEDICINE. 



for the right understanding of physiology and pathology, 

 bv placing them at the root of medical education. 

 Chemistry has influenced medicine from the days of 

 alchemy onwards ; Paracelsus and Van Helmont stand 

 out as picturesque figures in its history. In England the 

 rise of physics and chemistry began in Harvey's lifetime 

 with those meetings of scientific men which later gave 

 birth to the Royal Society. It must not be forgotten 

 that the work of such men as Boyle, Hooke, Lower and 

 Mayow practically solved the problem of respiration not 

 long after Harvey's death — a problem second only in 

 importance to that of the circulation — though a century 

 was to elapse for its full meaning to become clear with 

 the discovery of oxygen. Every advance in physics and 

 chemistry has borne fruit for us in its turn ; to-day we 

 can almost affirm that the chief issues in physiology and 

 pathology are to be sought in the chemical activities of 

 the human body. These, again, are bound up with 

 physical conditions, and there is one modern branch of 

 chemistry, the possibilities of which are only beginning 

 to be appreciated in medicine. If we reflect that the 

 body, from a chemical point of view, consists almost 

 entirely of colloidal compounds, the behaviour of which 

 is still imperfectly understood, it will be realised that 

 advances in colloidal chemistry are destined to throw a 

 flood of light upon the processes of vital activity. 



The doctrine of evolution has scarcely received the 

 attention it merits as a factor in modifying the opinions 

 of medical science. So long as it was believed that the 

 body, with all its natural functions, had been created 

 from the first in its present condition, there was little 

 room for inquiry into the origin of those functions, and 

 still less into that of morbid processes. Darwin has 

 changed all this, as a single instance will suffice to show. 

 Metchnikoff's studies on the comparative pathology of 

 inflammation have taught us that this is not a diseased 

 state, but a purposeful reaction against injury, gradually 

 perfected in passing up from the lower to the higher 



