8o8 



BIOPHYSICAL PHENOMENA 



[PT. Ill 



A certain number of investigators have occupied themselves with 

 the examination of the effects produced on developing eggs by en- 

 vironments of varying osmotic pressure. Morphological studies of 

 this kind are fairly numerous, but the present summary is confined 

 to those with a physiological bearing. Perhaps the most complete 

 is that of Vies & Dragoiu, who introduced the conception of "pression 



8 10 12 14 16 18 20 22 24 26 28 30 



Osmotic pressure in atmospheres 

 Fig. 194. A, experimental; B. theoretical. 



osmotique d'arret". They thought that, if one could determine the 

 osmotic concentration at which development ceased, it might be 

 possible to calculate the "energy of segmentation" or of development 

 itself. I shall return to this notion in the section on Energetics; 

 here only that part of the work which relates to osmotic 

 pressure will be considered. Placing the fertilised eggs of Strongylo- 

 centrotus lividus in solutions of glucose in sea water, they made a 

 statistical study of the effects produced. From 25 to 30 atmospheres, 

 the effect was almost inappreciable, perturbations of development 



