ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 355 



feeding is continued are capable of undergoing growth and physiological 

 senescence again from the stage represented at the end of the starvation 

 period. Susceptibility of the ectoderm and body wall increases from 

 the beginning of starvation, while susceptibility of the alimentary tract 

 at first decreases very markedly, and later increases. All the facts at 

 present known indicate that, except for the decrease in functional meta- 

 bolism in the alimentary tract, the rate of oxidation increasas during 

 starvation in Plauaria. J. A. T. 



Susceptibility to Lack of Oxygen during Starvation in Planaria. — 

 C. M. Child {Amer. Jouni. Physiol., 1911), 49, 403-19). Suscepti- 

 bility of ectoderm and body wall to lack of oxygen, as measured either 

 by loss of motility or by disintegration, increases progressively during 

 starvation up to at least four months. The' susceptibility to lack of 

 oxygen of the animal reduced by starvation is about the same as, or 

 slightly higher than, that of a fed, growing animal of the same size. The 

 change in susceptibility to lack of oxygen during starvation is in the 

 opposite direction from that which occurs during growth and progres- 

 sive development in fed animals, and* in the light of the facts already at 

 hand concerning CO2 production, oxygen consumption, and suscepti- 

 bility to KNC, must be considered as evidence of an increase in rate of 

 oxidation during starvation. J. A. T, 



Oxygen Consumption in Feeding and Starving Planaria. — L. H. 

 Hyman {Amer. Journ. Physiol, 1919, 49, 377-402). The oxygen 

 consumption increases markedly for several hours after the ingestion of 

 food ; it then begins to fall ; and by the following day the metabolism 

 has increased again to a marked degree. The oxygen consumption 

 continues to fall in the early days of starvation, reaching a minimum 

 value within the first two weeks. The oxygen consumption then 

 begins to rise,* and at the end of a period of prolonged starvation 

 it is much higher than in animals starved only a few days. There are 

 similar data in regard to other animals. It may therefore be concluded 

 that starvation increases the metabolic rate of organisms, and that 

 starved organisms are metabolically in a condition similar to that of 

 young organisms. J- A. T. 



Respiratory Metabolism in Planaria. — G. D. Allen (Amer. Journ. 

 Physiol., 1919, 49, 420-73). The oxygen consumption of Planaria 

 maculata and P. agilis decreases progressively during starvation at 

 constant temjterature, more rapidly at first and somewhat more slowly 

 later. The body weight also decreases during starvation, and the worms 

 becomes smaller in body dimensions. The rate of oxygen consumption 

 per unit of body weight in starving P. maculata and P. agilis decreases 

 rapidly during the first few (7) days, due to the decreasing accelera- 

 tive effect of food residuum from the previous feeding. At the end 

 of this period (7 to 14 days) the rate of oxidations reaches a constant 

 level, which is maintained for several weeks in P. agilis. During this 

 period the starvation results in a decrease in the body weight of at least 

 one-half of the original. The ingestion of food by starving specimens 

 results in a great increase in the oxygen consumption. After this initial 



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