THE METABOLISM OF EGGS, I 



57 



-70 



tq-60 



•6 

 ^-50 



k_ 



Oi 



e-40 



o 



c; 

 o 



"o -30 

 o 



"2-20 



5 



c 

 o 



O 



-10 



=1. 



+10 



+20 



10 



20 



30 

 t (min.) 



40 



50 



FIG. 9. — Metabolism of eggs of Paracentrotus lividus, before and after fertiliza- 

 tion. F, addition of spermatozoa. Gas phase, air. /, with 0-2 ml. 10% KOH 

 in the centre well of the manometer flask; //, without KOH. Both curves 

 corrected for sperm respiration. T° C, 20. 



field was due to Holter & Zeuthen (1944), who found that the 

 respiration of unfertilized eggs of Ciona intestinalis (Linn.) de- 

 clined with time after removal from the female. A few years later, 

 Borei (1948, 1949), using the Cartesian diver technique, examined 

 the variation in the Oo uptake of unfertilized sea-urchin eggs 

 {Psammechinus miliaris) with time after removal from the ovary. 

 His results are shown in Fig. 11. If it were possible to measure the 

 respiration of unfertilized sea-urchin eggs immediately after 



