THE CAUSATION OF DISEASE. 3 I I 



in certain cell-structures. In this case, all the positive con- 

 ditions of healthful cell action (I allude to the tissues primarily 

 and chiefly affected by the drug) such as the presence of 

 oxygen, food-stuffs, &c, obtain ; therefore, the opium must 

 render the S abnormal, otherwise the proper inter-action would 

 occur. The only alternative supposition is that the drug so 

 acts upon the cell-E as to render the positive conditions im- 

 perfect. This, indeed, occurs in some poisons — e.g., CO, which 

 seizes upon the O needful for the tissues. All those poisons 

 which do not modify the E so as to render the positive conditions 

 imperfect, must react upon the cell and modify its molecular 

 structure, in such a way as to prevent the proper inter-action 

 of S and E. It is obvious, however, that when rapid recovery 

 occurs, this molecular dislocation cannot be very serious, and 

 hence we may practically disregard the existence of structural 

 change in this class of malady. But if, on the other hand, 

 the administration of a poison be persisted in for a long time, 

 or any habit capable of producing functional disorder be 

 systematically indulged, it is well known that permanent 

 structural alteration may ensue ; and this fact suggests that 

 some structural alteration must attend even a temporary 

 functional disorder. 



A large number of the functional disturbances which occur 

 in what may be called the genuinely structural diseases would, 

 considered by themselves, come under the class of disorders we 

 are now considering, such functional disturbances being caused 

 by secondary mal-E. The faintnessin aortic regurgitation from 

 the irregular supply of blood to the brain affords an example. 

 Often the secondary mal-E consists of a poison, as in Bright's 

 disease, and I have already had occasion to allude to the profound 

 structural changes and fatal consequences directly traceable in 

 this disorder to the retention of nitrogenous excreta in the 

 blood. 



h. Diseases in which the S is abnormal when the E operates 

 upon it. — It is these disorders to which the term u Functional 

 Disease " is more commonly applied. The so-called " neuroses n 

 afford the best example of this class. If an individual is exposed 

 to an averagely healthy E and develops one of the neuroses, 

 there must be a structural deficiency in some part of the 



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