BIOPHYSICAL PHENOMENA 



[PT, III 



Fremiet investigated in some detail the osmotic relations of Sabellaria 

 eggs. Placing them in solutions of glucose of A varying from 

 — 0-566° to — o-686°, he measured their volume with a micrometer 

 scale and found, as was expected, a regular change; thus at — 1-135° 

 the calculated volume was 21-9. io~^ c.c, and at — 3-73° it was 

 9-95 . 10"^ c.c. Assuming that the membrane is impermeable to 



^ 6 

 >» 



^2 



Urea solubion 

 Sucrose solution 

 Theorebical curve 

 corrcspondinc) to -, 



perfect semi-permeability 

 of the egg membrane 



NaCL 

 CaCL2 

 Theorebical curve 



2 3 4 5 6 



Molarity of solution 



— Zone of* normal development 



Fig. 190. 



) 



2 3 4 5 



Molarity of solution 



Fig. 191. 



anything except water, Faure-Fremiet calculated the imbibition at 

 the different osmotic pressures. The normal Sabellaria ^gg contains 

 2-25 gm. of water for each gm. of solid, therefore a table was con- 

 structed showing the amount of water experimentally found in the 

 eggs in the different sugar solutions, and the amount of water which 

 should theoretically have been there. The observed and calculated 

 values corresponded very well, as can be seen in Fig. 190, from 

 which Faure-Fremiet concluded that it would be right to assume 

 that the egg-membranes were permeable only to water. The 



