CHAPTER IX 



SOME PROBLEMS IN THE PHYSIOLOGY OF THE PROTOZOA 



" Die psychischen Vorgange im Protistenreich sind daher die Briicke, welche die che- 

 mischen Processe in der unorganischen Natur mit dem Seelenleben der hdchsten Thiere 

 verbindet." VERWORN. 1 



ALL animals are subject to disintegration and waste of substance 

 through oxidation, and to reintegration and renewal of substance 

 through the addition of new materials. Waste and renewal are 

 usually spoken of together under the head of metabolism, and 

 together they constitute one of the essential properties by which 

 living matter is distinguished from non-living. When renewal of 

 substance exceeds its waste, the phenomenon of growth results, and 

 growth leads to reproduction. In the higher animals these various 

 functions are distributed among many organs, but in the Protozoa 

 they are all performed by the single cell. The simplest of living 

 forms, these organisms naturally invite a comparison of their functions, 

 on the one hand, with those of the higher animals, and, on the other 

 hand, with the physical and chemical operations of inorganic nature. 

 A modern attitude on the second of these comparisons is taken by 

 Verworn, an ardent opponent of the old conception of a specific vital 

 force, different from the forces of the inorganic world. " An ex- 

 planatory principle," says Verworn, " can never hold good in physi- 

 ology, in reference to the physical phenomena of life, that is not also 

 applicable in chemistry and physics to lifeless nature. The assump- 

 tion of a specific vital force in every form is not only wholly super- 

 fluous, but inadmissible." 2 This extreme reaction from the old 

 vitalistic point of view appears to be somewhat premature ; for, as 

 Driesch, Whitman, Wilson, and many others have suggested, there 

 exists in every organism a power of adaptation and certain coordinat- 

 ing factors by which the organism acts as an individual or a unit, 

 notwithstanding the fact that its body is composed of a great number 

 of chemically different substances. At the present time these coordi- 

 nating factors and the power of adaptation transcend physical or 

 chemical analysis, and raise the lowest protozoon immeasurably 

 above inanimate objects, and perhaps justify, in a modern sense, the 

 much-abused term " vitalism." 



1 Psycho- Prof isten Studien, p. 211. 2 Lee's Verworn, p. 46. 



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