122 SYMBIOSIS 



from abnormal or pathological growth and evolution. Such 

 study is apt to reveal not only a few diagnostically interesting 

 data, but, what is more, it reveals the fundamental Economy 

 of Nature, with its demand for definite duty, definite constitu- 

 tion, and definite integrity, a demand made on all participants 

 in the cosmic scheme, organic or inorganic, in the interest of ?]1. 

 The " normals " may thus be viewed as an expression of the 

 requirements of mutual accommodation of all systems in the 

 cos os. Biological " normals " in especial may be viewed as 

 connected with biological accommodation, past and present, 

 of the organism. 



Let us take as an example the " normals " of respiration 

 and of feeding. So far as respiration and nutrition are con- 

 cerned, as is well known, plant and animal to a certain extent 

 mutually complement each other. It is a case of past mutual 

 evolution, of simple and collective Symbiosis. Without the 

 symbiotic share of the plant and without adequate degrees of 

 symbiotic reaction on the part of the animal, the normals of 

 respiration and of nutrition existing in the physiological economy 

 of the animal could never have been evolved or maintained. 

 I go further and declare that without Symbiosis nothing but 

 chaotic action and reaction could have taken place. We have 

 seen that but for the restraints entailed by the symbiotic 

 regime, the conduct and the feeding methods of organisms are 

 apt to become chaotic, whilst the organism itself becomes 

 debauched and tends towards monstrosity and general abnor- 

 mality. 



The breathing, so Dr. Haldane tells us, " is more or less 

 regulated to correspond with the consumption of oxygen and 

 the production of carbon dioxide in the body." It is thus obvious 

 that the " normal " of respiration is intimately connected with 

 work, with the general biological activities and the biological 

 relations of the animal. Symbiosis, as we have seen, implies, 

 systematic and constant though modest and wholesome activity, 

 which means regular and wholesome exercise for the lungs, thus 

 enabling them to regulate breathing in an economical manner. 

 It is also evident that the supply of carbo-hydrates by the 

 symbiotic plant must largely determine the carbon dioxide 

 production of the animal. The capacity of the plant to supply 

 carbo-hydrates depends in turn upon the treatment and the 

 general support it receives from the animal as the biological 



