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PHYSIOLOGY: ANDERSON AND LUSK 
size. The latter v/as finally fed thyroid and began to metamorphose 
within a week. Both tadpoles were almost albinotic and from a recent 
paper by Allen it seems possible that in both larvae the hypophysis 
was abnormally developed or lacking. It is obvious that the pro- 
duction of a definite hormone and not the calory value of food is the 
limiting factor for the duration of the larval period. 
4. Conclusion. — The experiments show that Drosophila has a temper- 
ature coefficient for the duration of life of the order of magnitude of 
that of a chemical reaction. Since the animals used in our experiments 
were absolutely free from microorganisms this influence of temper- 
ature on the duration of life cannot be attributed to bacterial poisons. 
It was found, moreover, that the duration of the pupa stage is at 
each temperature proportional to the duration of the larval stage and 
that the same proportionality exists between the duration of the life 
of the insect to the larval stage, as far as our present experhnents go. 
Since we know that the duration of the larval stage is determined by 
a specific hormone we are compelled to consider the possibility that the 
duration of life is also primarily determined by the formation of poison- 
ous substances or a hormone in the body. 
1 Loeb, J., Arch. ges. Physiol., Bonn, 124, 1908, (411); Mocre, A. R., Arch. Entw.-Mech., 
Leipzig, 29, 1910, (287). For a fuller discussion of the subject see Loeb, The Organism as a 
Whole, New York, 1916. 
2 Loeb, J., and Northrop, J. H., these Proceedings, 2, 1916, (456). 
3 The experiments on the duration of life of the imago at 10° and 15° are not yet com- 
pleted. From present indications it seems that for 15° the duration of life is in the neigh- 
borhood of ninety days, which agrees with the value expected according to the theory. At 
10° the flies have been alive for ninety days and have not yet begun to die. 
THE INTERRELATION BETWEEN DIET AND BODY CONDITION 
AND THE ENERGY PRODUCTION DURING MECHANICAL 
WORK IN THE DOG 
By R. J. Anderson and Graham Lusk 
PHYSIOLOGICAL LABORATORY, CORNELL UNIVERSITY MEDICAL COLLEGE. NEW YORK CITY 
Read before the Academy, April 16, 1917 
A dog weighing 8 kgm., in poor nutritive condition, was received into 
the laboratory. His basal metabolism, as measured during a period 
of absolute rest eighteen hours after partaking of an adequate stand- 
ard diet, was 17.6 calories per hour. Traveling at the rate of 2.5 miles 
(4.0 km.) per hour he required ILO calories above the basal to move 
his body 1000 meters during the period beginning about eighteen hours 
after food ingestion, whereas 11.2 calories were required if 70 grams of 
