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THE QUARTERLY REVIEW OF BIOLOGY 



these experiments were carried out. He 

 found that, in general, the carbon dioxide 

 output decreased as the larvae approached 

 the chrysalid stage. In the pupa the 

 carbon dioxide output generally decreased 

 one third to one fourth and rose again. 

 Weinland (36), in his studies on the blow 

 fly, utilized the gaseous exchange of the 

 organism as a basis for estimating the 

 chemical changes occurring during me- 

 tamorphosis. He found that the larvae 

 liberated ammonia, whereas in the pupae 

 uric acid was produced. His experi- 

 ments with metabolism in general indicate 

 a markedly low carbon dioxide output at 

 the beginning or early stages of pupation, 

 which is followed by a period of rest. 

 In later stages, however, an increase in 

 the gaseous exchange of the organism 

 took place. Tangl (31) obtained results 

 from metabolism experiments on the silk- 

 worm similar in many respects to those of 

 Weinland. 



Parhon (n) studied the influence of 

 temperature on the gaseous exchange of 

 bees in the various seasons. She used 

 thirty grams of bees — about six hundred 

 insects — and found that with the advent 

 of summer the exchange increased with 

 rising temperature from 10 to 37°C, but 

 decreased at a temperature of 40 to 45 . 

 She concluded from these observations 

 that the bees must possess a heat-regulat- 

 ing mechanism. Parhon also made ob- 

 servations on the gaseous exchange of 

 flies, which, she found, rose regularly 

 with increasing temperature, following 

 very closely van't Hoff's Law. (For an 

 increase in temperature of ten degrees 

 centigrade, the rate of any reaction is 

 approximately doubled or trebled.) 



SlowtzofF (x6) observed the influence 

 of temperature on the gaseous exchange of 

 insects, principally ants and manure beetles. 

 He found that the exchange went up 

 with rising temperature, but that an inter- 



val of twelve degrees existed, during 

 which it remained constant. This inter- 

 val lay between 12. and 2.4 for the manure 

 beetle and between xo and 34 for the 

 ant. The respiratory quotient was higher 

 for the ant than for the manure beetle. 



Von Briicke (34) and von Linden (35) 

 worked with the chrysalides of several 

 butterflies. The former observed that the 

 carbon dioxide output rose with rising 

 temperature. Von Linden found that the 

 respiratory quotient during the night was 

 0.76 and during the day only 0.66. 



Battelli and Stern (2.) observed the 

 oxygen consumption and carbon dioxide 

 output at different temperatures for the 

 May-beetle, and for all stages in the meta- 

 morphosis of the silkworm and the fly. 

 Adult flies consumed the most oxygen and 

 gave off the most carbon dioxide of all the 

 stages studied. These workers noted a 

 decrease in the respiratory exchange when 

 the temperature was raised beyond a 

 certain limit. They found, furthermore, 

 that the exchange usually increased in the 

 first few hours at a high temperature and 

 regained the normal or fell to a lower 

 level later. Krogh (13) showed that in 

 a number of forms and over nearly the 

 whole range of temperature at which 

 normal development took place the 

 velocity of embryonic development was a 

 linear function of the temperature. Krogh 

 determined the carbon dioxide output of 

 the chrysalides of the beetle, Tenebrio 

 molitor, at different temperatures from 

 zi° to 33°C. The results indicated that 

 the total metabolism, so far as that can 

 be judged from determinations of carbon 

 dioxide exhalations, was constant over the 

 range of temperatures investigated. There 

 was no optimum temperature for the 

 pupal development. The relation be- 

 tween the temperature and the average 

 carbon dioxide production could not, 

 therefore, be expressed satisfactorily by 



