1444 LIFE : OUTLINES OF GENERAL BIOLOGY 



Another milestone was Wohler's synthesis* of urea in 1828, for 

 the building up of this characteristic organic substance from simple 

 inorganic materials made the first breach in the blockading wall 

 between what goes on in non-living Nature and what goes on in 

 tlie living body. It was a first — yet in principle decisive — shock to 

 the doctrine that organic substances could not be made except by 

 organisms; and it was the beginning of that brilliant succession of 

 synthetic achievements which have yielded not only sugars and 

 alcohols, but such complex substances as salicylic acid, indigo, 

 madder, adrenalin, and thyroxin. In the synthesis of amino-acids 

 the creative biochemist is drawing near to the artificial production 

 of proteins — hammering at the gates of Life's citadel. But apart 

 from the synthetic triumphs which followed, and stiH follow, 

 Wohler's great step, there was the blazing of a new trail. The pro- 

 ducts and processes of the living body were no longer in a preserve 

 for the physiologist; they were illumined by the analytic and 

 synthetic methods of the biochemist. 



With the name of Claude Bernard (1813-1878) several great 

 steps are associated. He established experimental physiology on a 

 firm footing; he discovered the glycogenic function of the liver; he 

 was one of the far-off anticipators of the hormone-producing role 

 of the ductless glands. But it is mainly to him that there should be 

 traced the illuminating idea of the twofold aspect of the normal 

 chemical routine of the body, which is at once or by turns con- 

 structive and disruptive, up-building and down-breaking, winding- 

 up and running-down, storing and spending. In more technical 

 language he distinguished in the metabolism of the organism its 

 two main processes — anabolism and katabolism, and thus generalised 

 the chemico-physical aspect of the moving equilibrium of life. 



Not less important for the general biological outlook was Claude 

 Bernard's Phenomenes de la Vie communs aiix Animaux et mix 

 Vegetaux (1878), for it brought into clearness and prominence the 

 fundamental similarity in the main vital processes (photosynthesis 

 excepted) in the two apparently contrasted sub-kingdoms of 

 Organisata. As a recent worthy appendix to this classic may be 

 ranked the ingenious investigations of Sir Jagadis Chunder Bose on 

 the sensitiveness and other animal-like features of plants. 



Man's pollination of the date-palm goes back to remote antiquity, 

 but a scientific appreciation of the sexes of plants did not come till 

 near the end of the seventeenth century, when Camerarius proved 

 that pollen is usually indispensable, if there are to be fertile seeds. 

 This was a great step towards a deeper recognition of the unity of 

 plant and animal life, and what was at first somewhat crude in 

 expression was elaborated into the demonstration of an intimate 

 correspondence between the reproductive phenomena of plants and 

 animals. 



