TRANSACTIONS OF SECTION B. 651 



methods of producing many of these very compounds which we claim to have 

 synthesised. There can he no manner of doubt that a large proportion, if not a 

 majority, of the natural products which have been prepared artificially are not 

 synthesised by the animal or plant in the sense of building up at all. They are 

 the results of the breaking down — of the degradation — of complex molecules into 

 simpler ones. I urge, therefore, that if in the laboratory we can arrive at one of 

 these products by decomposing a more complex molecule by means of suitable 

 reagents, we have a perfect right to call this a synthesis, provided always that the 

 more complex molecule, which gives us our compound, can be in its turn synthe- 

 sised, by no matter how many steps, from its constituent atoms. Thus oxalic acid 

 has been directly synthesised from carbon dioxide by Kolbe and Drechsel by pass- 

 ing this gas over potassium or sodium amalgam heated to 360°. Whether the 

 plant makes oxalic acid directly out of carbon dioxide we cannot at present state ; 

 if it does it certainly does not employ Kolbe and Breschel's process. On the other 

 hand this acid may, for all that is known, exist in the plant as a product of degra- 

 dation. Many more complex acids, such as citric and tartaric, break down into 

 oxalic acid when fused with potash. Both citric and tartaric acids can now be 

 completely synthesised ; therefore the formation of oxalic acid from these by potash 

 fusion is a true synthesis. 



The illustration given will make clear the point which I am urging. The dis- 

 tinction between a synthesis and a mode of formation vanishes when we can obtain 

 a compound by the breaking down of a more complex molecule in all those cases 

 where the latter can be completely built up. If we do not expand the meaning of 

 synthesis so as to comprise such cases we are simply shutting the door in Nature's 

 face. It must be borne in mind that the actual yield of the compound furnished 

 by the laboratory process does not come into consideration, because it may be 

 generally asserted that in most cases the artificial processes are not the same as 

 those which go on in the animal or plant. The information of renl value to the 

 physiologist which these syntheses give is the sugtrestion ihat such or such a 

 compound may possibly result from the degradation of this or that antecedent 

 compound, and not from a process of building up from simpler molecules. 



The Beaeing of Chemical Synthesis on Vital Chemistet. 



With these views — the outcome of structural chemistry — the chemist and 

 physiologist may join hands and move fearlessly onwards towards the great 

 mystery of vital chemistry. In considering the results of organic synthesis two 

 questions always arise as it were spontaneously : How does nature produce these 

 complicated molecules without the use of strong reagents and at ordinary temper- 

 atures? What bearing have our laboratory achievements on the mechanism of 

 vitality ? The light shed upon these questions by experimental investigation has 

 as yet flickered only in fitful gleams. We are but dwellers in the outer gates, 

 waiting for the guide who is to show us the bearing of modern research on the 

 great problem which confronts alike the physicist, the chemist, and the biologist. 

 The chemical processes that go on in the li\ing organism are complex to an extent 

 that is difficult to realise. Of the various compounds of animal or vegetable origin 

 that have been produced synthetically some are of the nature of waste products, 

 resulting from metabolic degradation ; others are the result of zymolytic action 

 within the organism ; and others, again, are secondary products arising from the 

 action of associated Bacteria, the relationship between the Bacteria and their host 

 being as yet imperfectly understood. The answer to the question how nature 

 produces complicated organic molecules will be much facilitated when the 

 physiologist, by experiment and observation, shall have made possible a sound 

 classification of these synthetical products based on their mode of origination in 

 the organism. 



The enlargement of the definition of organic synthesis which I have advocated 

 has been rendered necessary by the consideration of certain questions which have 

 arisen in connection with the present condition of chemical discovery in this field. 

 What evidence is there that any one of the 180 compounds which have been pre- 



