124 PLANT PHYSIOLOGY 



hardly any one is properly fitted to carry out this task. I readily 

 admit that there are many others who could have done this better 

 than I. Yet I believe that I have drawn for you some of the more 

 important outlines of the development of our science. 



As a chief result of my analysis I have shown the evidence of con- 

 tinual change, of separation and union, of scientific work. Not only 

 are the results gained in divided labor united within small special 

 fields to the advantage of science. Perhaps of still greater advantage 

 is the contact and union of studies which are apparently Jieteroge- 

 neous. Fruitful ideas and methods come often enough not from the 

 narrowly circumscribed field of study, but to a certain extent from 

 outer and apparently foreign realms. And just in the results thus 

 obtained, the facts teach us that all human wisdom, all which to-day 

 furthers the struggle after knowledge, forms only one great unity, 

 which to the individual comes with more reality the deeper he has 

 gone into science. 



Yet one thing I would not leave unmentioned at the close. Out of 

 the depths of the past, science has emerged, at first a mixture of truth 

 and fiction, of the results of study which are often intertwined with 

 strange embellishments, inventions, and dark hints. In the older 

 writings, and further on in the literature up till the present time, - 

 in lessening amount, to be sure, religious conceptions, or wonder 

 at creation, appear side by side with the results of research. But 

 throughout the conviction rings that these reflections, much as the} 7 

 may be in themselves justified and partake of the noblest aspirations 

 of the human mind, must be separated from science, and belong 

 to another sphere. 



And yet another form of vague inner impulse still rules, even 

 though it has already been much suppressed, in the realm of science. 

 the metaphysical element. A trace of the metaphysical, as salt to 

 the bread, will perhaps always remain, because, as already shown, 

 thoughts which help the weakness of the human understanding are 

 as crutches to the lame. We may be allowed to compromise with 

 these small remnants of a once rampant metaphysics, if we enter- 

 tain such ideas only so long as they do not come into clash with 

 our experience, and really help us in the sure way of observation. 

 There are indeed optimistic theorists who expect that natural science 

 will reach complete fruition only after the last trace of metaphysics 

 has been eradicated. 1 



1 E. Mach, loc. tit., p. 7. 



