60 Scientific Proceedings, Royal Dublin Society. 



would be gained by any of these cbanges. One or other of them 

 is now conducive to progressive absorption of energy by the 

 organism, and one or other occurs, most generally the best of 

 them, subdivision. Two units now exist, the total mass imme- 

 diately on division is unaltered, but paths for the more abundant 

 absorption of energy are laid open. 



The encystment of the protoplasm (occurring under conditions 

 upon which naturalists do not seem agreed') is to all appearance 

 protective from an unfavourable environment, but it is often a 

 period of internal change as well, resulting in a segregation 

 within the mass of numerous small units, followed by a break-up 

 of the whole into these units. It is thus an extension of the basis 

 of supply, and in an impoverished medium, where unit of surface 

 is less active, is evidently the best means of preserving a condition 

 of progress. 



Thus, in the organism which forms the basis of all modes 

 of life, a definite law of action is obeyed under various circum- 

 stances of reaction with the available energy of its environment. 



Similarly, in the case of the more complex leaf, we see in its 

 extension in a flattened form, and in the orientation of greatest 

 surface towards the source of energy, an attitude towards available 

 energy causative of accelerated transfer. There is seemingly a 

 principle at work, leading to the increase of organic activity. 



Many other examples might be adduced. The gastrula stage 

 in the development of embryos, where by invagination such an 

 arrangement of the multiplying cells is secured as to offer the 

 greatest possible surface consistent with a first division of labour; 

 the provision of cilia for drawing upon the energy supply of the 

 medium, and more generally the specialisation of organs in the 

 higher developments of life, may alike be regarded as efforts of the 

 organism directed to the absorption of energy. When any par- 

 ticular organ becomes unavailing in the obtainment of supplies, 

 the organ, no longer preserved to heredity by the action of natural 

 selection, in the course of time becomes aborted or disappears.^ 

 On the other hand, when a too ready and liberal supply renders 

 exertions and specialisation unnecessary, a similar abortion of 



1 However, "In no way comparable with death." Weisman, "Biological 

 Memoirs," p. 158. 



2 Claus, "Zoology,"?. 157. 



