688 



THE RESPIRATION AND 



[PT. Ill 



O Luciani S^Piutti 

 ♦ Farkas (i) 

 O „ (2) 



Excessive amounts of oxygen exerted a marked toxic action. In 

 normal development (after the winter diapause was quite passed 

 through), the amount of carbon dioxide given out per day per kilo of 

 eggs rose quite regularly until at hatching the value was 259 times 

 what it had been initially. In Fig. 136, constructed from the data 

 of Luciani & Piutti, the graph of this process is given ; it does not, of 

 course, represent metabolic rate, for nothing is known of the weight 

 of protoplasm present at different stages. During the whole period 

 55-1 18 gm. of carbon dioxide were given off by i kilo of eggs, repre- 

 senting a loss of 1-5 per cent, of the carbon originally present. 

 Throughout the whole period, including the time of hibernation, the 

 behaviour of the eggs as ,,_ 

 regards weight was variable, 

 for sometimes they became ^ 

 heavier, owing to absorp- ^ 

 tion of water in a humid o- 

 atmosphere, and sometimes gg 

 they lost weight, owing to s 

 exhalation of water in a dry "^ 

 atmosphere. Physiologically '^ 

 they were apparently un- > 

 affected, except that more > 

 carbon dioxide was evolved q 

 weight for weight during the ^ 

 wet periods than during the S 

 dry ones^ 



The respiratory quotient 

 gave a curious result, for 

 while it was about 0-97 at ^^' ^^ ' 



the beginning of the developmental period it then rose steadily, passing 

 unity when between a third and a quarter of development had been 

 completed, and rising to 1-305 by the time of hatching. Luciani & 

 Piutti considered that carbohydrates were being combusted through- 

 out development. 



Some of the less important conclusions of Luciani & Piutti were 



Days of development after the end of 

 hibernation 



1 Ashbel, in later work, obtained curves very similar to Bodine's, showing first a some- 

 what intense respiration, which dies away after 4-5 days, giving place to the quiescent 

 period's almost imperceptible gas-exchange. The silkworm egg respires much less before 

 than after fertilisation (see p. 640) and gives out a gas, probably CO2, for some time 

 after laying, even when not fertilised (see pp. 712 and 819). 



