DEFENSES OF THE BODY 133 



to the ordinary methods of observation there is no 

 sign of derangement of health, no indication of 

 impaired function, although we are well aware that 

 these putrefactive substances have distinct poison- 

 ous properties. In these cases, we cannot say that 

 there is disease. This is out of the question in any 

 ordinary sense of the term. Yet we know that a 

 further exaggeration of this process of poison absorp- 

 tion will lead surely to the development of symptoms 

 and entry into the realm of the definitely pathological. 

 So we have to recognize that we are dealing with a 

 condition on the borderland between health and 

 disease. There are very many examples of states 

 which cannot be strictly called disease, yet cannot be 

 classed as physiological. The study of such states 

 has shown us clearly that, in general, we must regard 

 disease, not as a vicious something wholly foreign to 

 the body and able to invade it, but as the expression 

 of slight, considerable, or extreme derangements of 

 biological processes. The healthy, animal organism 

 at any given instant represents a combination of func- 

 tions in which the balancing of opposing tendencies 

 is a prominent feature. A perfect balancing of op- 

 posing tendencies makes for inaction and stability, 

 while oscillation in balance within narrow limits is 

 characteristic of normal activities. On the other 

 hand, a disturbance of the balance between opposing 

 functions, leading to wide oscillations or to the 

 partial or complete suppression of one of two op- 

 posing tendencies or activities, constitutes disease, 



