324 L. V. HEILBRUNN. 



discovered. Thus it is probable that benzol or xylol would 

 behave as toluol, and that many other alcohols and esters could 

 have been added to those given in the table. Such experiments 

 would scarcely add material for the general argument. 



On the other hand it might be thought that the eleven sub- 

 stances in the table represent only a few out of the many that 

 I have tried. It perhaps not infrequently happens that experi- 

 menters suppress the record of their failures. But in these 

 experiments practically every substance selected because of its 

 effect on surface tension gave the expected result. There were 

 only three exceptions and in two of these cases I performed only 

 a single experiment with a single concentration of the reagent. 

 Moreover in each of these three cases the reagent employed had 

 some secondary effect on the egg. I shall consider each case 

 in detail. 



Ethyl Urethane. 3 per cent, ethyl urethane had practically no 

 effect, although in longer exposures (5-7 minutes) a few eggs 

 with polar bodies were observed. The reagent has some action 

 on the jelly that I have not analyzed. Possibly it is a shrinkage 

 effect. Two minutes after the egg entered the solution it was 

 surrounded by queer looking bubbles. Fifteen minutes later 

 the bubbles had disappeared and their place had apparently 

 been taken by a zone of radiating lines. 



Nitromethane. I used a 5 per cent, solution of nitromethane 

 and exposed the eggs to it for intervals of from ^-10 minutes. 

 No polar bodies were produced as a result of the treatment. 

 Exposure for 4 minutes followed by transfer to normal sea-water 

 resulted in rupture of the vitelline membrane and disintegration 

 of the egg. The eggs left in the nitromethane solution showed 

 a queer transformation. They lost their spherical shape and 

 flattened out into discs resembling huge red blood corpuscles. 

 In addition to this queer effect the reagent also appeared to have 

 some action on the jelly, for some morphological changes were 

 visible around the egg. The nature of these changes I did not 

 stop to investigate. 



Acetone. Two concentrations of acetone were tried. 25 per 

 cent, acetone did not produce membrane elevation when eggs 

 were exposed i-n minutes. 50 per cent, acetone produced 



