Anaholism and Specicdisation. 199 



specialisation took the direction of instability in the products 

 of anaholism. 



I have attempted to bring together some facts regarding 

 the difference of animals and plants in their metabolism, 

 and also other points drawn from sexual reproduction and 

 allied subjects which seem to have a bearing on the question. 



As a result of anaholism in animals, we get the energy 

 with accompanying excretion of material as shown during 

 life, and the highly unstable organic products of the body 

 after death. This body is quickly broken up into compara- 

 tively simple organic compounds. Stable structures of the 

 animal body after death, such as bone, shell, and the like, 

 consist chiefly of elements which do not enter largely into 

 the composition of living protoplasm. Exceptions to this 

 are seen in the chitin, keratin, etc., of dermal structures ; and 

 the cells, which consist largely of these substances, might be 

 looked upon as having suffered death from katabolism, owing 

 to a decrease in nutrition. On the other hand, the more 

 specialised plant structures are comparatively stable after 

 death. These structures are in large part organic in composi- 

 tion, consisting chiefly of the essential elements of living 

 protoplasm, and appear to be more or less synthetic in nature. 



Over-nutrition in animals tends to retard specialisation, 

 and, in fact, to bring about what is termed degeneration. 

 This is well seen in parasites, which lose the organs of high 

 animal specialisation and gain in powers of simple growth 

 and less specialised methods of reproduction. That this 

 degeneration has been brought about partly by cessation or 

 reversal of natural selection seems probable, but the high 

 degree of nutrition attained by the parasitic mode of life 

 would appear in large measure to lead to this result. In 

 animal life, therefore, high nutrition favours reproduction, 

 but tends to degrade it from the sexual to the asexual type. 

 The results of excessive nutrition in plants are not easy to 

 observe, as it is impossible to make a plant assimilate more 

 carbon than its leaf-area will allow. However, Wallace states 

 in " Tropical Nature " that the greater the vegetation the less 

 the conspicuousness and the number of flowers, not only in 

 the Tropics but elsewhere, and this is especially observable 



VOL. XV. P 



