1 42 SYMBIOSIS 



as a branch of the tree of life, the branch receiving its main 

 directions of growth from the tree, which in the first place furnishes 

 pabulum and restraints adequate to the widest contingencies of 

 life the autonomy of the branch being subordinate to that of 

 the tree. The well-being of the tree depends in turn upon the 

 work of its branches ; tree and branches mutually determine each 

 other. That individuality looms behind the processes of 

 Nutrition and Reproduction, is adumbrated by Prof. Farmer, 

 when he says, for instance, that : 



In the evolution of the more complex plants, the cells the primitive 

 individuals become organised into a higher individuality, or when he 

 shows that the nucleus, the true determinator of hereditary qualities and 

 of the chemical changes proceeding within the protoplasm, is the seat of 

 individuality. 



To make individuality the starting point of our investigations, 

 is undoubtedly the best method of obtaining light on the other- 

 wise mysterious ways of nutrition. Such method enables us 

 to transcend the narrow confines of physical, chemical and 

 physiological divisions and leads to a comprehensive view of the 

 matter without injustice to any one associated factor. It throws 

 light on the great significance of food habits for instance. It 

 enables us better to realise how it is that different food habits 

 must eventually entail different lines of evolution. 



Prof. Farmer recognises that there is a great change of point 

 of view if instead of thinking of the multiplication of cells as 

 reproduction in the abstract (irrespective of individuality), we 

 think of the unit organism (the individual) undergoing trans- 

 formation . The latter point of view he would apply more specially 

 to the higher, i.e., more complex forms of Reproduction, e.g., 

 when new colonies of cells, and not new cells merely, are started ; 

 that is to say, when individuality and the necessarily implied 

 autonomy come more pronouncedly into purview. 



Coming to sexual reproduction proper, we learn that it 

 occurs in almost all the divisions of the animal and vegetable kingdoms, 

 although it has not as yet been detected in some of the lower groups. 

 These consist either of organisms of extreme simplicity, or of those in which 

 we have grounds for believing that sexuality has been lost, probably in 

 connection with special conditions of nutrition. In some of the higher 

 plants the sexual function has degenerated, though we cannot clearly 

 trace the loss to any definite cause. 



Bio-economically speaking, the loss referred to in this passage 

 is one that has to do, I believe, with bad methods of food-getting, 



