Discussion on the chemical and physical basis of pharmacological action, 12 November, 1936

This subject is of basic importance in pharmacology and in chemo­therapy and is becoming of increasing importance in physiology and in enzyme chemistry. Hence any quantitative information that can be obtained is of great value. These reasons justify the attempt to apply methods of physical chemistry to living cells, even though the latter are very unsuitable material for such work. It must, however, be remembered that such an attempt implies using methods for purposes for which they are not intended, and this is always a dangerous procedure. The living cell is so complex and its mode of organization and structure so imperfectly known that the number of uncontrolled and even unknown variables is always great, whilst unavoidable sources of error such as individual variation prevent any high degree of accuracy being attained. Only the simplest methods of mathematical analysis are appropriate in such conditions, and formal proof of any hypothesis can rarely be obtained. We must therefore be content with finding explanations for drug action which are reasonably probable and involve the fewest unproven assump­tions.