3o8 E. G. Spaulding 



Making the correction for a room temperature of 23.5 C. in 

 accordance with the formula, pt=po (i +.00367^), the osmotic 

 pressure of the above diluted solution, /. e., the pressure sufficient 

 to inhibit the first segmentation and therefore equal to the result- 

 ant internal pressure, is 7.32 atmospheres. 



For the second segmentation, the numerical value of this inhib- 

 iting pressure, as computed in a similar manner from the recorded 

 figures above, is 6.53 atmospheres, and for the third, 6.40 atmos- 

 pheres. 



MEASUREMENTS OF DIAMETERS AND AXES 



Average diameter of 20 typical eggs = .072 mm.; radius = .036. 

 Area (4 n r^) = .0164 sq. mm. 

 Volume (I ;r r^) = .000214 cu. mm. 



Tw^o-cell stage: each cell an oblate ellipsoid. Average axes of 

 20 typical segmented eggs: 



Long axis {d') 068 mm. 



Short axis (d) 039 mm. 



Area('^'''^'^"xW)=.oii; 



mm. 



for each cell; for both .0236 sq. mm. 



Volume {i 7t d d'' X 2) = .000206 cu. mm. for both cells together. 



From these values it is evident that, v^hereas the area has in- 

 creased by .0072 mm., the volume has remained the same. 



It would now seem as if the data were at hand whose numerical 

 values could be substituted in the "work integral" 



W = 



I V d p 



which becomes W = v [p^ ~p2) when the volume remains constant, 

 as in this case. However, before doing this, the question must be 

 answered, as to what may be the value of that pressure which is 

 due to the tension of the surface film or membrane of the develop- 

 ing egg. For it might seem that the resultant internal pressure 

 before and after each segmentation was equal to, not alone the 

 opposing osmotic pressure of the surrounding sugar sea-water 



