DOUGLAS MARSLAND 



121 



be done. The present data were derived from the unfertilized eggs of the 

 Arbacia, because centrifugal forces high enough to measure the exceedingly 

 great gelational strength of the furrowing eggs were not available. More- 

 over, the concentration of ATP required to give a measurable effect on 



Fig. 9. ATP-induced fortifi- 

 cation of the plasmagel struc- 

 ture. Centrifugal measurements 

 and at various pressures on the 

 unfertilized eggs of Arbacia 

 pimctulata. Data from Landau 

 et al, 1955. 



2 4 G 8 



PRESSURE - 1000 L3S /SO IN. 



Fig. 10. ATP-induced 

 strengthening of the plasmagel 

 structure. Measurements at vari- 

 ous temperatures on the un- 

 fertilized eggs of Arbaci punctu- 

 lata. Data from Landau et al., 

 1955. 



o 



^200 



iij 



il 150 



z 

 o 



u. 



o 



z 



Ui 



UJ 



100 

 90 

 80 

 70 



60 

 50 



ATMOSPHERIC 

 PRESSURE 



CONTROL; 

 NO ATP 



_l_ 



10 



15 20 



TEMPERATURE 



25 



30 



the gel structure was twice that used in demonstrating the increased 

 strength of the furrowing reaction. Virtually no effects were obtained when 

 adenosine monophosphate, adenosine or inorganic phosphate was used in 

 place of ATP (11). 



