Summary 183 



thinking in general and is suggested by the triumphs 

 of the synthetic chemist, who builds up complex car- 

 bon-compounds from simple materials. Very striking 

 are the recent experiments of Professor Baly and his 

 colleagues, who have been able, with the aid of light 

 only, to build up formaldehyde from carbon dioxide 

 and water, and to bring about a union of nitrites with 

 the formaldehyde. The problem of the origin of living 

 creatures upon the earth remains admittedly very 

 obscure, but the probability of a natural integration 

 has certainly increased. While there is no known ex- 

 ception to the experimental induction omne vivum e 

 vivo, we are not warranted in making this into a 

 dogma. 



2. The most important process in the world is the 

 photosynthesis that occurs in the green leaf. Utiliz- 

 ing part of the radiant energy which shines through 

 the complex green pigment (chlorophyll), the green 

 leaf is able from carbon dioxide and water to build 

 up formaldehyde, which becomes the basis for sugars 

 and starch. A continuation of the synthetic process 

 results in proteins, which are essential parts of the 

 physical basis of life (protoplasm). The carbon- 

 compounds thus built up furnish materials for the 

 plant's growth and energy for its activities ; and they 

 form the fundamental food-supply of the animal 

 world. Moreover, by the utilization of the carbon 

 dioxide of the air, and the return of oxygen, green 

 plants have for ages been making a breathable at- 

 mosphere, and they continue to keep it "good." It is 

 this fundamental process of photosynthesis that has 



