INFLUENCE OF ACTIVITY ON PROTEID METABOLISM. 915 



difference in the amount of sugar of the blood passing to and from an 

 active muscle has been obtained by Chauveau and Kauf mann ; 1 such 

 differences as are found generally fall within the limits of experimental 

 error. Chauveau 2 has further endeavoured to show that in dogs 

 muscular work is not effected at all at the expense either of the 

 proteids of the body or of the food ; but, as I. Munk has pointed 

 out, the results obtained cannot be accepted as conclusive. 3 That 

 glycogen disappears both from the liver and from the muscles of 

 dogs, and from the " surviving " excised muscles of the frog, con- 

 comitantly with the production of muscular work, 4 is held to be an 

 argument in favour of this work being done at the expense of this 

 carbohydrate. Under certain circumstances, however, the glycogen of 

 the muscles may be caused to entirely disappear, although they are still 

 capable of performing a large amount of work, which must, under 

 these circumstances, be otherwise derived, however probable it may 

 be that under normal circumstances the oxidation of dextrose or 

 glycogen plays an important part in its production. 



In support of the view that muscular energy may be largely derived 

 from the oxidation of carbohydrate materials, it has been observed by 

 Tiegel, 5 that the Japanese rickshaw runners consume rice in large 

 quantities, and at frequent intervals, during their periods of work, 

 whereas on off-days they live mainly on a flesh diet. 6 



Pfliiger 7 kept a dog of 30 kilos, weight in equilibrium upon perfectly lean 

 meat, containing a very large preponderance of proteids over non-proteids. 

 When caused to pass from a condition of rest to hard work, it lost flesh if kept 

 on the same diet, until it assumed a lower position of ^"-equilibrium, but main- 

 tained or even added to its weight if the amount of flesh was increased 500 

 grms. per diem ; about 50 per cent, of the potential energy of the additional 

 proteid appearing as work. If now, whilst in ^-equilibrium on lean flesh, fat 

 and carbohydrate were added to the diet, these were not utilised for the pro- 

 duction of energy, but were stored as fat ; hence, Pfliiger argues, the living 

 tissue prefers to use the proteid, and only takes non-proteid if insufficient proteid 

 is offered to it. It should, however, be pointed out that Pfliiger's dog was, 

 with its purely proteid diet, in a condition of extreme emaciation, 8 and the cir- 



1 Compt. rend. A cad. d. sc., Paris, 1887, tome civ. pp. 1126, 1352, and 1409. Similar 

 results (disappearance of sugar from blood passing through active muscles) have been 

 obtained by Morat and Dufourt (Arch, de physiol. norm, et path., Paris, 1892, p. 327), who 

 also found a certain disappearance after the work, which they suppose due to glycogen stored. 



2 With Contejean, Compt. rend. Acad. d. sc., Paris, tome cxxii. pp. 429, 504. 



3 Verhandl. d. physiol. Gesellsch. zu Berlin, 8 Mai, in Arch. f. Physiol., Leipzig, 1896. 



4 0. Nasse, Arch.f. d. ges. Physiol., Komi, 1869, Bd. ii. S. 97 ; also Weiss, Sitzungsb. d. k. 

 Akad. d. Wissensch., Wicn, 1876, Bd. Ixiv. S. 288; Marcuse, Arch. f. d. ges. Physiol., 

 Bonn, 1886, Bd. xxxix. S. 425; Manche, Ztschr. f. Biol, Miinchen, 1889, S. Bd. xxv. 

 164 ; and ibid., 1877, Bd. xiv. S. 473. 



5 Ibid., 1883, Bd. xxxi. S. 607. 



6 U. Mosso and Paoletti (Atti d. Accad. d. Lincei, Koma, 1893) and V. Harley 

 (Proc. Roy. Soc. London, 1893, p. 480, and Journ. Physiol., Cambridge and London, 1894, 

 vol. xv. p. 97) using the ergograph of A. Mosso, found that they could perform a greater 

 amount of voluntary muscular work when a large amount of cane-sugar was added to the 

 diet. Experiments of this nature are, however, liable to a psychical error, and, as a 

 matter of fact, experiments by Langemeyer (with Stokvis) made upon different persons 

 failed to give similar results (see discussion in Brit. Med. Journ., London, 1895, vol. ii. 

 pp. 1280-1285). 



7 Arch.f. d. ges. Physiol., Bonn, 1891, Bd. 1. S. 98, and Bd. Ii. S. 317. 



8 It may be noted in this connection that the " Banting cure " for obesity depends upon 

 the principle of selecting a diet not necessarily insufficient, but consisting mainly of lean 

 meat. As in the case of Pfliiger's dog, the tissues under these conditions use up the body- 

 fat, which thus becomes gradually reduced in amount. 



