Symptoms and their interpretation / by James Mackenzie.

  • Mackenzie, James, 1853-1925.
Date:
1912
Catalogue details

Licence: In copyright

Credit: Symptoms and their interpretation / by James Mackenzie. Source: Wellcome Collection.

    36/332 (page 12)
    5. The Parsimony of Hypotheses.—In seeking in any given case for the causation of a group of symptoms, however far apart they may be in situa- tion, and however diverse in character, it is far more probable that the nexus will be found, not in a diversity of causes producing the symptoms sever- ally, hut in some condition capable of producing the group. The application of this method, called by logicians the law of the parsimony of hypotheses,” should be rigidly applied in all cases; and, although it may not always be successful, the search for a connection between the several phenomena will reveal many facts previously overlooked or neglected, and give a guide to further evidence. A good illustra- tion of the application of this law is seen in the examination of cases with a focal lesion in the brain or spinal cord. Certain lesions of small extent may produce symptoms widely separated, such as paraly- sis in one part of the body, and sensory disturbances in another, while disturbed functions may be detected in certain viscera. When the nerve supply of these different parts is considered, it will he found that at some point the different tracts lie close together, so that it becomes fairly certain the lesion will be found at this place. The value of this method will be appre- ciated in deal in o' with visceral disease, where it is shown that a diseased viscus, besides affording evidences of impaired function and change in form, may also produce a focal irritation of the spinal cord, resembling in many respects a focal lesion, and in- ducing widespread symptoms of great diversity. The application of this law becomes a matter of considerable difficulty when the more prominent symptoms are due immediately to one or more organs,