4 2o SCIENCE PROGRESS 



called functional is that their correlating basis, their cause, is 

 in the patient's imagination. A disease is a mental construct. 

 It exists nowhere but in the mind of the physician ; and con- 

 sequently we find that many diseases, such as plethora, mar- 

 asmus, biliousness, sluggish action of the liver, chill on the 

 liver, and so forth, are wholly imaginary. But the physician 

 holds no monopoly of imagination. The patient has his share ; 

 and if the physician can imagine a complete disease, the 

 patient can imagine the basis of a disease, and not infrequently 

 he does so. That the basis of certain ' functional ' diseases 

 is in fact imaginary is shown by the fact that their symptoms 

 may be anatomically and physiologically impossible. A 

 paralysis or an anaesthesia, for instance, may be incompatible 

 with the distribution of the nerves ; and apart from supposi- 

 tion, no experienced physician can possibly doubt the existence 

 of diseases whose basis is in the patient's imagination, and 

 nowhere else. Taking hysteria as the type of ' functional 

 disease, it is found that, whatever the subsequent symptoms 

 may be, it always begins as an inability or incapacity ; and 

 there is no difficulty in conceiving that an inability or in- 

 capacity may be imaginary. The patient imagines that she 

 cannot stand, walk, move her arm, apply her mind, endure 

 noise or light, or do something else that she has always been 

 able to do ; and as long as she is convinced of her disability, it 

 is a real disability. Undeceive her, and it disappears. That 

 the causal nexus is in the imagination, and in that alone, is 

 proved by the erratic distribution of the disorders. They do 

 not correspond or fit in with any natural grouping of organs 

 or functions. Anaesthesia of one arm may be correlated with 

 paralysis of the opposite leg, and loss of half the field of vision 

 in only one eye. Numbness of the little finger may accom- 

 pany numbness of the thumb of the same hand. Such a 

 distribution cannot be accounted for by any material cause. 

 No structural change, whatever its nature, could correlate 

 them all. The correlating cause must be the imagination. 



By an ' organic ' disease, we understand a disease that is 

 not of this nature. We may not know what the correlating 

 cause of the disorders is, but we believe that it is not imaginary. 

 We know that the correlating cause of some diseases is gross 

 anatomical damage. Such diseases are certainly ' organic.' 

 We know that the correlating cause of others is microscopical 



