474 TKANSACTIONS OF SECTION T. 1 



In the same way the common reaction of tissues, which I have so far ascribed 

 to their possessing some substance in common, may arise from community of 

 physical relationship, and I wish to avoid the implication borne by the word 

 ' substance,' which I have used in the widest sense, such as is justified perhaps 

 only by its historical employment in theological or philosophical controversy. 

 The reaction of living tissue to chemical agents may arise from a specific 

 arrangement in its molecule, but may equally be attributed to the arrangement 

 of the molecules themselves. And the curious relationships in the reactions 

 of different tissues may indicate, not any common chemical factor, but a common 

 arrangement of the aggregate molecules. We are far from being able to decide 

 with even a show of probability which of these alternatives is the correct one, 

 and my object to-day has been to draw attention to these relationships rather 

 than to attempt their elucidation. Hitherto the speculative pharmacologist has 

 been much engaged in comparing the chemical relationship of the drugs which 

 he applies to living tissues ; much useful knowledge has been incidentally 

 acquired, and the law has been formulated that pharmacological action depends 

 directly on, and can be deduced from, chemical structure. This view, first 

 elaborated in this country, has in recent years shared tlie fate of other English 

 products in being advertised from the housetops and practically claimed as the 

 discovery of more vociferous investigators. On examining the evidence, old 

 and new, one cannot help feeling that attention has been too much directed 

 to those instances which conform to tlie creed, while the far more numerous 

 cases have been ignored in which this so-called rule fails. The difficulties are 

 very great; for example, what cliemical considerations can be adduced to explain 

 why the central nervous tissues react differently to bromide and chloride, 

 while to the other tissues these are almost equally indifferent ; or how can the 

 known chemical differences between potassium and sodium be brought into 

 relation with the fact that tliey differ in their effects in almost every form of 

 living tissue? 



Less attention has been paid to the other factor in the reaction, the propertie.^ 

 of the living tissue which lead one cell to react to a poison, while another fails 

 to do so. I have pointed out some curious relations between different organs, 

 but much needs to be done before any general view can be obtained. Further 

 detailed examination of the exact point at which poisons act, and much greater 

 knowledge of the physical characters of the drugs themselves and of the rePation 

 of colloid substances to these characters, are needed. We must attempt to 

 classify living tissues in groups not determined by their morphological or even 

 functional characters, but by their ability to react to chemical agents. Advance 

 is slow, but it is continuous, and if no general attack on the problem is possible 

 as yet, our pickets are at any rate beginning to give us information as to the 

 position of the different groups to be attacked. And when a sufficient number 

 of these C[ualitative reactions have been ascertained for any form of living 

 matter, it may be possible for some Darwin to build a bridge from the struc- 

 tural chemistry of the protein molecule to the reactions of the living cell. We 

 can only shape the bricks and mix tlie mortar for him. And my purpose 

 to-day has been to indicate how the study of the effects of drugs on the living 

 tissue may also contribute its mite towards the great end. 



The following Rej^orts and Papers were then received :— 



1. Report on tlic Ductless Glands. — See Eeport-s, p. 30.5. 



2. Report on ilie Structure and Function of the Mammalian Heart. 

 See Reports, p. 304. 



3. Report on the Significance of the Electromotive Phenomena 

 of the Heart. 



