8o6 



BIOPHYSICAL PHENOMENA 



[PT. Ill 



similar curve to Faure-Fremiet's for the effect of heat on imbibition 

 of water, and in collaboration with Neukomm for the effect of pH 

 on imbibition (see Figs. 192 and 193). McCutcheon & Lucke, on 

 the other hand, maintained that for Arbacia pH had no effect, but 

 their measurements were rather few. The spermatozoa were, Ephrussi 

 found, less susceptible to heat than the unfertilised eggs. The normal 

 osmotic pressure of the egg-contents in Strongylocentrotus lividus was 

 25 atmospheres, i.e. practically isotonic with sea water. Heating at 



> 



-d 



\P 



2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 



TempercLtare (°C) 



Fig. 192. A. Strong^iocentrotus . B. Sabellaria. 



different temperatures for a short time led to [a) a rise in the internal 

 osmotic pressure, and [b) a subsequent fall, the whole curve forming 

 a peak, the angle of which was the more acute the higher the tempera- 

 ture. Ephrussi concluded that two irreversible processes were in 

 operation. 



Perhaps the most interesting result obtained by Faure-Fremiet on 

 Sabellaria eggs in this connection was the finding that the eggs 

 obeyed the Boyle-Mariotte law. Ephrussi & Neukomm could not 

 show that this was so for Strongylocentrotus eggs. If j&F = K holds good, 

 the eggs should swell in hypotonic solutions and shrink in hypertonic 



