CHAPTEK II 



LIVING MATTER: ITS FUNDAMENTAL PROPERTIES 



CONTENTS. Vital metabolism and phenomena of nutrition and reproduction. 

 2. Vital metabolism and phenomena of excitability and sensibility. 3. Laws of 

 stability and variability of living species. Critical examination of Theory of 

 Evolution ; Darwinism, and Neo-Lamarckism. 4. Evolutionary theories of Nageli, 

 Weismann, De Vries. 5. Distinctive characters of plants and animals : (a) Doc- 

 trine of Linnaeus ; (&) doctrine of Cuvier ; (c) doctrine of J. R. Mayer, Dumas, 

 Liebig. 6. Different forms of plant and animal metabolism : (a) Nitrifying 

 bacteria ; (6) green plants ; (c) a-chlorophyllous plants ; (d) herbivorous and 

 carnivorous plants. Bibliography. 



THE fine morphological organisation and highly complex chemico- 

 physical structure of elementary organisms, while sufficiently 

 distinctive in character to differentiate non-living matter from 

 living bodies, are not adequate to distinguish the living body from 

 the dead, or from the products elaborated by the living. As a 

 matter of fact, our knowledge of cytological structure depends 

 mainly, and the data we possess in regard to the chemical composi- 

 tion of the cell depend entirely, upon observations made on the 

 dead organism. 



Yet it is upon the cytological and physico-chemical structure 

 of the cell that the physiological activity and functions common 

 to all living beings are founded, and it is by these that they are 

 characteristically distinguished from non-living matter. 



General Physiology has of late undergone a remarkable 

 development in the direction of philosophical interpretation. We 

 must here confine ourselves to summarising the most definitely 

 ascertained conclusions passing over the many hypotheses by 

 which it is attempted to fill the unbridged gaps, and keeping 

 strictly to what may serve as the foundation of scientific culture, 

 and preparation to the study of human physiology. 



I. Life is essentially characterised by instability and movement, 

 by the constant transformation of matter, with a corresponding 

 evolution and accumulation of energy, which is exhibited in uni- 

 cellular as in multicellular organisms, in plants as in animals. 

 The name Metabolism (//cra/^oArj, change) has been given to these 

 physico-chemical changes of living protoplasm as a whole. It is 



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