THE PROCESS OF EXCITATION 97 



tegration of the dextrose molecule, its first point of attack must 

 obviously be sought in the aldehyd group. Here would be sit- 

 uated the activator, as it were, for the whole carbon chain, from 

 which, as by a spark, the entire series of links would be ignited. 

 In an anoxydative disintegration of dextrose as observed in 

 anaerobic as well as in aerobic organisms, provided the latter have 

 an insufficient supply of oxygen, the dextrose molecule, by 

 enzymic action as a result of the splitting off of carbon dioxide, 

 is converted into substances having a comparatively large carbon 

 content. The best-known example of this anoxydative disin- 

 tegration is the formation of alcohol by fermentation in which 

 the dextrose molecule is split up by the yeast into alcohol and 

 carbon dioxide. (CgHioOa = 2C2H5OH -f SCO,.) Instead of 

 the production of alcohol and CO2 we may have other enzymic 

 actions with the formation of other carbon-containing disintegra- 

 tion products, such as lactic acid, fatty acids, hydrogen, etc. Of 

 course in such an anoxydative disintegration, which does not lead 

 to the formation of such simple combinations as carbon dioxide 

 and water, the quantity of energy set free is much less in amount 

 than in complete oxydative decomposition, the energy production 

 of the alcohol fermentation being only 11 per cent of the latter. 

 In order to produce the same amount of energy as in the former, 

 a much greater number of molecules is required. \\'e find, there- 

 fore, that the anoxydative type of disintegration develops either 

 only where the respiratory substances are present in sufficient 

 amounts, as for instance, in the case of yeast cells, existing in 

 nutritive solutions rich in sugar; or where the chemical and 

 energy transformations occur only to a limited extent, as, for 

 example, in the presence of low temperature. In this respect 

 putter'^ has demonstrated in the leech that at a higher tempera- 

 ture, the oxydative, at a lower, the anoxydative, decomposition 

 predominates. These are important facts in that they show us 

 the superiority of oxydative to that of the anoxydative disinte- 

 gration in the cell economy. This is of particular interest when 

 we consider those organisms in which great demands are made 



1 A. Putter: "Der Stoffwechsel des Blutegels (Hirudo medicinalis L)." I Theil. 

 Zeitschrift fiir allgemeine Physiologic Bd. VI, 1907. II Teil. ebenda Bd. VII, 1908. 



