LECTURE XXIX. 

 OUTLOOK. 

 I. 



WE have not even approximately exhausted the large domain of 

 physiological-chemical investigation in the discussion of our knowledge 

 concerning the chemical processes which take place in plant and animal 

 organisms. We have merely been able to touch upon the fundamental 

 principles upon which the science rests. To be sure, our knowledge is still 

 incomplete, and the explanation of many phenomena has resulted solely 

 from the play of the imagination. On the other hand, the progress of 

 the exact sciences is constantly bringing new methods to the aid of physi- 

 ological chemistry, and in this way we are being led to more definite prob- 

 lems, so that we are hopefully looking forward to the further development 

 of the field. Little by little the unknown becomes the known. Direct 

 proofs gradually replace the indirect conclusions. The physiological 

 chemist is gradually breaking away from the observation of a single 

 individual. It is becoming very evident that satisfactory results can 

 be obtained only when the investigation is carried out with as many dif- 

 ferent organisms as possible. The broader the foundations, the greater 

 the scope of observation, and the more varied the conditions are under 

 which certain physiological processes are studied, the less danger there 

 is in arriving at biased conclusions. Just as morphology developed into 

 an independent science only by extensive comparative investigations 

 and by the careful consideration of the anthropogeny of each individ- 

 ual species, so we shall expect to obtain from comparative physio- 

 logical-chemical investigation the answer to many problems and to 

 receive new impulses for further inquiry. Just as an organ which is 

 functionally unimportant e.g., an apparently superfluous bone may 

 be in the eyes of a zoologist an eloquent proof of a common origin with 

 a certain class of animals, and just as the botanist is able to conclude 

 from the similarity of the flora of our highest Alpine peaks and that of 

 the Far North that there is an intimate relation between these two 

 regions, so we may certainly hope to meet here and there with chemical 

 processes which will lead us from the present into the far-distant past. 

 What an infinite perspective is opened to us by a glimpse at the wonderful 

 flower tapestry of the Alpine heights, this so foreign and so characteristic 



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