12 



SCIENCE. 



[N. S. Vol. XXII. No. 549. 



must be ingested instead of 100, if that 

 represents the starvation requirement. 

 Rubner-" explains that the cells of the body 

 do not require more energy after meat in- 

 gestion than in starvation, but that the 

 heat produced by a preliminary cleavage 

 of proteid into dextrose on the one hand, 

 and into a nitrogen containing rest on the 

 other, while yielding heat to the body does 

 not furnish the actual energy for the vital 

 activities of the protoplasm. This is fur- 

 nished principally by the dextrose derived 

 from the proteid. Although it is necessary 

 to abandon the older theory which pro- 

 nounces glycogen (or dextrose) a direct 

 cleavage product of proteid, still the ex- 

 planation of Rubner remains tenable if 

 interpreted in the newer light. If the 

 energy requirement of the cell remains 

 constant at 100, even after the ingestion of 

 140 calories of proteid, then 71.4 per cent, 

 of the total heat value of the proteid is the 

 quantity actually used for the vital proc- 

 esses. Since it has been shown in the 

 writer 's laboratory that meat proteid yields 

 58 per cent, of dextrose in metabolism, it 

 may be calculated that 52.5 per cent, of the 

 total energy of proteid may be available 

 for the cells in the form of sugar. A bal- 

 ance of 19 per cent, must be obtained from 

 other compounds, while 28.5 per cent, of 

 the total heat value is wasted as heat with- 

 out ever having been brought into the serv- 

 ice of the life processes of the cells. Per- 

 haps this 28.5 per cent, of heat loss repre- 

 sents the quantity produced by the cleavage 

 of proteid into amino bodies and the de- 

 nitrogenization of these radicles. 



The constancy of the energy require- 

 ment in metabolism makes difficult the ex- 

 planation of the action of the various fer- 

 ments found in the body. These are of two 

 varieties, hydrolytic and oxidizing, but 

 these from the very principles of our 



-' Rubner. ' Gesetze des Energieverbrauclis,' 1902, 

 p. 380. 



knowledge must be subservient to the re- 

 quirement of the living cells, and not them- 

 selves masters of the situation, as, for ex- 

 ample, they are in the autolysis of dead 

 tissue. It seems to be the requirement of 

 the mechanism of cell activity which de- 

 termines metabolism, and not primarily the 

 action of enzymes, whose influence appears 

 to be only intermediary. 



FriedenthaP*' shows that proteid, col- 

 loidal carbohydrates, fats and soaps are 

 not oxidizable in the cellular fluids without 

 previous hydrolytic cleavage. After hy- 

 drolysis, however, the oxidases may effect 

 an oxidation of the smaller molecules. The 

 necessity of the hydrolytic ferment is seen 

 in the non-combustion of dextrose after the 

 extirpation of the pancreas, the organ by 

 which the ferment is supplied. Oxygen 

 and the oxidases are present in ample quan- 

 tity, but the sugar is not burned unless it 

 be broken by its specific ferment. In the 

 meantime the cell avails itself of a compen- 

 satory energy supply from other sources. 

 It is impossible to apply anything similar 

 to Ehrlich's side-chain theory to this con- 

 dition of affairs, for the metabolism does 

 not depend upon the satisfaction of chem- 

 ical affinities, but rather upon a definite 

 law of utilization of energy equivalents. 



However clearly formulated the laws of 

 metabolism may be, and many of them are 

 as fixed and definite as are any laws of 

 physics and chemistry, still the primary 

 cause of metabolism remains a hidden se- 

 cret of the living bioplasm. 



Graham Lusk. 



Ukiveksity and Bellevue 

 Hospital Medical College.. 



SCIENTIFIC BOOKS. 

 Notes on Anthropoid Apes. By the Hon. 



Walter Rothschild. 



This paper, in the last number of the Pro- 

 ceedings of the Zoological Society of London 



^^ Friedenthal, ' Verhandlungen der Berliner 

 Physiologischen Gesellschaft,' Archiv filr Physiol- 

 ogie, 1904, p. 371. 



