BIO-DYNAMICS 119 



and profitable when it is really co-operative and not merely competitive, 

 resting on increasing mutual aid instead of on mutual plunder. Species 

 as well as individuals co-operate just as classes and nations co-operate 

 in international exchange as well as individuals in a town or a factory 

 and always with immense mutual advantage. . . . Sexual reproduction 

 is, I hold, an instance of this successful co-operation of specially differ- 

 entiated individuals and, on a broader view still, I submit that the 

 organic world has been enormously advanced by the co-operation of the 

 specially differentiated plant and animal. But it must be co-operation 

 in which both gain, and not depredation in which one side, at any rate, 

 temporarily, loses. 



You refer to adaptation. I do not deny adaptation. I do not mean 

 that every adaptation comes under the head of co-operation. But I am 

 trying to show where it does and where it does not, in the same way as 

 T am trying to show where physiology ceases and where pathology begins. 



As regards cross-feeding compared to in-feeding, besides the fact 

 that in-feeding and especially parasitism, its extreme form, implies 

 depredation and not co-operation, in-feeding also involves the absorption 

 of the waste products and poisons in the organism preyed upon, and 

 this, with the usual concomitant over-stimulation of some functions 

 (e.g., reproduction) and atrophy of others from disuse, tends to disease, 

 degradation, and extinction. My generalisation is that Nature abhors 

 perpetual in-feeding. That in-feeding is quite possible and, for a time, 

 may even have its use, I deny no more than Darwin denied that " in- 

 breeding ' ' is conceivably sometimes of use. Other things equal, 

 however, cross-feeding is superior. 



As regards the young in-feeding while in utero, I do not regard 

 this as in-feeding for two reasons : first, that it represents a process of 

 self-development, i.e., discontinuous growth, and is merely an incomplete 

 fission during which the young depends as much on the maternal diges- 

 tive system as the mother's own organs and, f-econdly, after birth the 

 offspring is fed not on flesh, i.e., not on an indiscriminate carnivorous 

 method but on a specially prepared "love-food" eminently suitable, 

 non-stimulating, and not containing waste products or poison. (Cases 

 of embryonic gluttony and consequent reproductive nemesis represent 

 the penalty for the acquisition by the species of wasteful feeding habits. ) 

 So with the adult cross-feeding. The grain of cereals and pollen of 

 flowers are specially prepared products serviceable first for home use 

 and also available for co-operation with the animal world, as special 

 surplus manufactures are available for export trade to the advantage 

 of all concerned services being rendered in exchange, as for instance 

 distribution of seed, the saving of pollen as against wind fertilisation, 

 etc. In the apple and plum pulp a special food is manufactured for 

 export alone in return for services. 



