i EXCHANGE OF MATEEIAL 49 



It does not follow from what we have said that the ideal diet 

 should consist exclusively of either protein substances or sub- 

 stances derived from the animal world. On the contrary, a mixed 

 diet, or the addition of vegetable foods which contain a large 

 quantity of carbohydrates, is undoubtedly the one best suited to 

 man, more especially in our temperate climate. We purpose, how- 

 ever, to treat of the physiological theory of human nutrition as 

 fully as it deserves when we have considered the interesting 

 subject of energetic metabolism. 



EDITORIAL NOTE 



Accessory Food Factors or Vitamines. In any consideration of the question 

 of nutrition it is necessary to take into account the important recent work 

 which has shown that there are unknown but essential constituents of food 

 called vitamines, the absence of which leads to the deficiency diseases, such as 

 scurvy and beri-beri. The chemical nature and mode of action of these 

 substances are unknown ; two groups have been recognised, the fat-soluble A, 

 and the water-soluble B. The former is contained in butter, cod-liver oil, 

 and animal fats ; it is absent from vegetable oils and is not found in many 

 forms of margarine. Fresh animal foods and vegetables are important sources 

 of these vitamiues. 



Justice to this important subject cannot be done by means of a note ; the 

 reader, is advised to consult the recent special report (with bibliography) 

 issiu-d by the Medical Research Committee, Special Report Series, No. 38 

 (Vitamines), H.M. Stationery Office, London, 1919 ; also the article by F. G. 

 Hopkins, Brit. Med. Journ., 26th April 1919. 



BIBLIOGRAPHY 



The reader will find a complete list of the older literature on " the physiology 

 of exchange of material and nutrition" in the article by Voit (Hermann's 

 Handbueh der Physiologic, Bd. iv., Leipzig, 1881). 



Modern writings on the subject have been for the most part summed up in 

 Tigerstedt's comprehensive treatise (Nagel's Handbueh der Physiologic des 

 Mcnschen, Bd. i., ss. 331-547, Brunswick, 1909). 



On the subject of exchange of material during feasting : 



L. LUCIAXI. Fisiologia del digiuno. Florence, 1889. German translation by Dr. 



M. 0. Frankel. Hamburg and Leipzig, 1890. 

 C. LEHMANN, F. MULLF.K, I. HUNK, H. SENATOR, N. ZUNTZ. Arch, fur path. 



Anat. u. Physiol. u. klin. Med., 131, 1893. 

 J. E. JOHANSSON, E. LANDEUGUEN, K. SONDEN, R. TIGERSTEDT. Skand. Arch. 



Physiol. vii., 1897. 

 F. G. BENEDICT. The Influence of Inanition on Metabolism. Washington, 



Carnegie Institution, 1897. This is a large volume of 542 pages, containing a 



complete treatise on inanition. 



On the exchange of material during alimentation : 



PFLUGER. Arch. ges. Physiol. 1. and li., 1891 ; xcvi., 1903. 



BISCHOFF and VOIT. Die Gesetze der Ernahrung des Fleischfressers. Leipzig 



and Heidelberg, 1860. 



Vorr. Zs. Biol. ii., 1866; iii., 1867 ; v., 1869. 

 FEDEK. Ibid, xvii., 1881. 

 GRUBELI. Ibid, xlii., 1901. 

 FORSTEK. Ibid, ix., 1873. 



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