AGE DIFFERENCES IN METABOLISM OF PLAN ARIA. 40! 



2. The young of Planaria velata, produced by an asexual 

 process involving regeneration and a high degree of reorganization 

 of the body, consume about 100 per cent, more oxygen than the 

 worms from which they come. The greater difference in this 

 species is undoubtedly associated with the method by which the 

 young are produced. 



3. The sexually produced young of Planaria maculata consume 

 about 50 per cent, more oxygen than the sexually mature worms. 

 There is thus no significant difference between sexual and asexual 

 young, when the latter arise by ordinary simple fission. 



4. This result, that young worms have a higher metabolic 

 rate than old ones, is in accord with a considerable body of 

 literature on other forms leading to the same conclusion; and 

 confirms the work previously done in this laboratory upon this 

 same point by other methods. 



Allen, G. D. 



'ig Quantitative Studies on the Rate of Respiratory Metabolism in Planaria. 

 II. The Rate of Oxygen Consumption during Starvation, Feeding, Growth, 

 and Regeneration in Relation to the Method of Susceptibility to Potassium 

 Cyanide as a Measure of Rate of Metabolism. Am. Journ. Physiol., 

 Vol. 49, PP- 420-474. 

 Bert, P. 



'70 Legons sur la physiologie comparee de la respiration. Paris. 

 Benedict, F. G., and Talbot, F. B. 



'14 The Gaseous Metabolism of Infants. Carn. Instit. Wash. Publ. no. 201, 



168 pp. 



'15 The Phj - siology of the New-born Infant. Ibid., no. 233, 126 pp. 

 Bohr, Chr. 



'oo Der respiratorische Stoffwechsel des Saugethierembryo. Skand. Arch. f. 



Physiol., Vol. 10, pp. 412-433. 

 Bohr, Chr., and Hasselbalch, K. A. 



'oo Ueber die Kohlensaureproduction des Hiihnerembryos. Skand. Arch. f. 



Physiol., Vol. 10, pp. 149-173. 

 Bounhiol, J. 



'02 Recherches biologiques experimentales sur la respiration des Annelides 



polychetes. Ann. d. Sci. Nat. Zool., Vol. 16, pp. 1-128. 

 Child, C. M. 



'13 Studies on the Dynamics of Morphogenesis and Inheritance in Experi- 

 mental Reproduction. V. The Relation Between Resistance to Depressing 

 Agents and Rate of Metabolism in Planaria dorotoce phala and its Value 

 as a Method of Investigation. Journ. Exp. Zool., Vol. 14, pp. 153-206. 

 '18 Physiological Senescence in Hydromedusce. BIOL BULL., Vol. 34, pp. 49-63. 

 '19 A Comparative Study of Carbon Dioxide Production during Starvation 

 in Planaria. Am. Journ. Physiol., Vol. 48, pp. 231-257. 



