8 INTRODUCTORY 



hand in hand has been insisted upon so frequently and so emphatically 

 of late years by both classes of workers l . The publication of this 

 volume may possibly contribute towards this much-desired rapproche- 

 ment between the sciences. 



So far as modern science has been enabled to deal with the question 

 of the mode of origin of these vital products in the living organism, it 

 must be confessed that hitherto but little progress has been made. 

 The chemist at the present time may be said to be far in advance of 

 the physiologist in his contributions to biochemistry. "While large 

 numbers of definite vital products have been isolated, identified, and 

 synthesised in the laboratory, the course of development of these com- 

 pounds in the organism can hardly yet be said to have been satis- 

 factorily traced in any instance. The practical difficulties associated 

 with this kind of investigation are confessedly very great, but it must 

 be apparent to chemists that the study of the evolution of organic 

 compounds in the animal or plant has the most pressing claims upon 

 the attention of physiologists. "With the solution of the problems 

 furnished by such studies our knowledge of vital chemistry, and 

 through this of vital processes generally, is certain to advance by great 

 strides. Perhaps it is not going too far to say that the whole future 

 development of physiological chemistry lies in this direction. 



The chemical evolution in the living organism of one definite 

 compound of known constitution, if successfully traced, might lead to 

 the discovery of fundamental principles. It certainly must strike 

 chemists as being somewhat remarkable, in view of the importance of 

 the investigation of such problems, that more systematic efforts have 

 not been concentrated upon them by physiologists. The difficulties 

 surrounding the determination of the origin of such a comparatively 

 simple product as urea in the animal body or oxalic acid in plants, 

 or, again, the study of the origin and fate of amino-acids in the 

 growing plant, which has received so much attention of late years 

 from Schulze and others, will only serve to emphasise the necessity 

 for the vigorous prosecution of research in this field. The evolution 

 of definite products in the growing plant would appear to offer special 

 facilities for investigation, because the course of development of the 

 compounds might be followed by collecting and investigating such 

 well-characterised substances as are contained in many ethereal oils at 

 different stages in the life-history of the plant or of the part of the 

 plant which yields the oil. Some progress in this direction has been 

 made in France by Charabot, whose views concerning the development 

 of the terpene alcohols and ketones, which are referred to under these 

 respective groups, are worthy of special notice as examples of the 

 results of a kind of pioneering work which is much required. Such 

 research constitutes the common meeting ground of chemistry and 



1 See, for instance, Prof. W. D. Halliburton's address to the Section of Physiology at 

 the Belfast meeting of the British Association in 1902. Brit. Assoc. Kep. 1902, p. 771. 



