466 



L. V. HEILBRUNN. 



3456789 10 1E34567 



MINUTES 



FIG. 2. In the above figures the curves represent increase of diameter of 

 individual sea-urchin eggs in equal parts of sea-water and distilled water. (The 

 original size is an average measurement.) The continuous lines represent etherized 

 eggs, the broken lines control eggs, not exposed to ether. The concentration of 

 ether used was i per cent, by volume, and the eggs were first treated with i per 

 cent, ether in sea-water and were then transferred to i per cent, ether in equal 

 parts of sea-water and distilled water. The ordinates represent the diameter of 

 the eggs in arbitrary scale units, the abscissae show the number of minutes elapsed 

 after the entrance of the egg into the hypotonic solution. Similar results were 

 also obtained with 2 per cent, ether solutions, but the measurements are harder 

 to make as the eggs frequently rupture. 



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