INTRODUCTION xi 



which I attach great importance, may lead to the establishment 

 of a new organon of medicine. 



As regards this antithesis, once more, I contend that it is 

 essentially identical with that existing between health and disease. 

 My reasoning is as follows : Symbiosis means partnership 

 systematic, intimate and laborious. It exemplifies sound 

 Economics. Parasitism, on the other hand, means the denial 

 of such partnership, and the setting up of warfare. It exemplifies 

 unsound Economics. Now when we speak of healthy function 

 and " function " is a fundamental concept alike of Physiology 

 and of Biology we mean this : the due performance of " duties " 

 on the part of the units, which " duties," I submit, are none 

 other than obligations in partnership. Nor does it make any 

 great difference whether these duties are conceived of as physio- 

 logical rather than biological. In practice these spheres overlap, 

 for Nature knows no watertight compartments as between 

 Physiology, i.e., the functioning of the organism, and Biology, 

 i.e., the inter-relations of organisms and species. In the last 

 analysis, therefore, everything in Physiology or Biology turns 

 upon the performance of duties duties and partnerships. To 

 live is to be or not to be : in a relation of Symbiosis with the 

 rest of the world. Disturbed " function," i.e., disease, is, in the 

 main and broadly viewed, a disturbed balance due to a disturbed 

 or perverted partnership. Recent Pathology shows that we may 

 have a kind of " biological " disease superposed upon " physio- 

 logical " disease. That is to say a disease of the " species " 

 may grow out of a disease of unbalanced, because non-symbiotic 

 individuals ; although, as I insist again, the distinction is rather 

 verbal and due to our preference for watertight compartments 

 more than to any real break in the unity of disease. Disease, 

 in my view, is a continuous process continuous inasmuch as 

 the root-cause, the disturbance of balance, the unbalancing, 

 because non-symbiotic action, or, in other words, the divorce 

 from Symbiosis persists. And inasmuch as the cause persists, 

 disease persists and develops without respecting organs, or 

 organisms, or species ; it is " cosmopolitan," i.e., biological as 

 well as physiological. 



What tells most, and is almost the essence of disease, is the 

 loss of resisting power. And this loss, I contend, is universally 

 due to one great cause, namely, action or behaviour that is not 

 according to Symbiosis, i.e., systematic biological co-operation. 



