ENERGY METABOLISM 435 



liberation of energy, namely the glycolytic breakdown of 

 carbohydrates with the formation of pyruvic and lactic acids. 

 This view w^as put forward by A. Piitter^-^ as early as 1905, 

 and, considerably later, by A. Szent-Gyorgyi^^* who held that 

 glycolysis represents a more ancient attempt by nature to 

 use energy. Indeed, in all the representatives of the animal 

 kingdom so far studied, the presence of the glycolytic cycle 

 of degradation of carbohydrates has been established. As we 

 sa'^v above, glycolysis occurs in protozoa and other primitive 

 animals. O. Harnisch^^^ found glycolysis in a number of 

 groups of insects {Periplaneta, Carausius, Bombus, Apis, 

 Eristalis). Glycolytic enzymes have been isolated from the 

 wing muscles of the grasshopper.^^'' Various representative 

 species of worms {Schistosoma mafisoni /^'' Neoaplectana 

 glaseri,^^^ and Hymenolepis diminuta^-^) possess glycolytic 

 systems, while molluscs can also decompose carbohydrates 

 anaerobicallv.^^" 



At the conclusion of his extensive review of glycolysis P. K. 

 Stumpf"^ writes as follows : 



Since a multitude of animals have been analyzed for the 

 presence of the cycle, it becomes impossible to itemize the activity 

 of each animal and organ. In general all tissues of higher animals 

 ranging from the internal organs to parts of the eye such as 

 the cornea, the crystalline lens, and the retina have been found 

 to contain the galaxy of glycolytic enzymes. Indeed, it would be 

 difficult to demonstrate its absence in cell tissue. 



Nevertheless, in a brief listing of the tissues in which the 

 glycolytic system has been found unequivocally, hearts of the 

 eel, toad, turtle, and rat, cornea of the rabbit, retinas of the 

 guinea pig and lizard, chick embryos of different ages, leucocytes, 

 erythrocytes, frog embryos, semen from a variety of sources, 

 rabbit femoral and tibial bone marrow, human rib marrow, 

 mouse melanoma, Flexner-Jobling rat carcinoma (to mention a 

 few tumor tissues), gastric mucosa, brain and the various organ 

 tissues of the body have the glycolytic system as a functioning 

 unit. 



A systematic survey of the evidence for the presence of 

 glycolysis in representatives of various groups of animals may 

 be found in a number of review works, in particular that of 

 J. P. Greenstein and A. Meister.^^^ 



