THE STRUCTURE AND PROPERTIES OF PROTOPLASM. 59 



CORRELATED TOPICS. 



Summary of the distinctive properties of Protoplasm. 



Distinction between the physical and the ' vital '' properties of 

 Protoplasm. 



Difference between the external influences acting (c?) mechani- 

 cally, (/?) tonically, and (c) as stimuli. 



Nature of the release of energy causing- movement in the 



organism. 



Ecological aspects of direct effects of light and heat upon 



Protoplasm. 

 Effect of varying quantities of water upon the resistance of 



Protoplasm to heat and cold. 

 Desiccation of Protoplasm, and its ecological value. 



IMPORTANT LITERATURE. 



The standard general works. 



Davenport, C. B. Comparative Morphology, Parts I and II. 



(Xew York, Macmillan.) 

 Thurston, R. H. The Animal as a Machine and Prime 



Mover. Science, 1, 365, 1895. 

 Hermann, G. Studien iiber die Protoplasmastromung bei den 



Characeen. Jena, 1898. 

 Loew, O. The Energy of Living Protoplasm. London, 



1893. 



The Proteids of Living Matter. Science, 11, 930. 



Section 3. The Power of Organism-building by Protoplasm. 



L T p to this point you have studied Protoplasm as it occurs 

 .and works in single protoplasts. But, of course, Protoplasm 

 is not confined to these, but builds itself into great many-celled 

 organisms. Since, however, Protoplasm is a soft substance 

 possessing no strength for resisting the great mechanical strains 

 to which large organisms are necessarily subject, it must be 

 supported by a firm skeleton built by itself. This skeleton 



