Clinical science : illustrated by personal experiences / by Sir Thomas Lewis.

  • Thomas Lewis
Date:
1934
Catalogue details

Licence: In copyright

Credit: Clinical science : illustrated by personal experiences / by Sir Thomas Lewis. Source: Wellcome Collection.

    22/208 page 10
    If we were to confine the term disease to specific and closely defined conditions, then we should recognise for each disease its equally definite pathogenic cause. But as long as diseases are undefined, so long shall we be forced to looseness in assigning cause. In this direction it must be confessed that medicine is often regrettably slipshod, as when many and diverse causes of one “ disease ” are enumerated under “ etiological” headings. The words “ caused by,” as they are often used in such connection have no different meaning than the words “ associated with,” for we are in doubt if a causes b, b causes a, or a and b both result from a given set of circumstances ; one of these three relations would necessarily hold, if the association were invariable. A frequent source of confusion is that what is dealt with is not a disease but some particular manifestation of disease. Such a manifestation may seemingly arise in distinct sets of circumstance. If it is asked what is the cause of pathological dilatation of the heart ? The reply might be in the form of such a list as:—obstruction of the aortic orifice, coronary thrombosis, pernicious anaemia, diphtheria. The list may form an aid to empirical diagnosis, but the philosophical unsoundness of the statement is marked by its patent failure to convey the strict and whole truth. First the list is incomplete and cannot usefully be made comprehensive ; secondly, the statement fails to convey that in each and all of these states dilatation may not occur. In such a case the attempt to discover a common factor and to express this in clear language, often clarifies thought and may form the starting point of real progress. In the instances given we may formulate the cause in a deliberate phrase such as “ inability of a well-supplied heart properly to discharge its blood content ” ; this statement sets out to become philosophical and, as it is brought nearer to perfection, its value to rational thought and to investigation increases. Their inclusion in one phrase brings the factors of causation into proper perspective, and it becomes evident that inability to discharge contents may result from increased resistance at the outlet or from decreased power of the heart’s muscle to expel. But such statements, if they are to hold good, require for their construction close consideration of the malady from many angles. It is this consideration, and the reasoning involved with it, which open up new points of view and often lead to new and fruitful
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