224 L. V. HEILBRUNN 



ones. Moreover, in the tabulation of these experiments, I shall 

 attempt to reduce the data to the briefest possible form, omitting 

 many of the less essential observations. 



In order to compare the cytoplasmic viscosity of the treated 

 eggs with that of the normal controls, normal and treated eggs 

 were centrifuged simultaneously in separate tubes of the centri- 

 fuge. These comparison tests had to be made before the control 

 eggs segmented, and preferably at a time when the cytoplasmic 

 viscosity of the eggs was high. Thus only a limited period was 

 available, and it was impossible to test the viscosity of the eggs 

 in all the vials. Oftentimes it was necessary to repeat experi- 

 ments. It was always found that when a particular concentra- 

 tion of a reagent completely prohibited gelation, the eggs sub- 

 jected to this concentration never formed a spindle. This rela- 

 tion always held true. 



In the following description, frequent reference is made to per 

 cent solutions. In most cases, solutions of liquids in liquids are 

 referred to, and in such instances, per cents by volume are under- 

 stood. By this I mean cc. of solute per 100 cc. of solution. In 

 the few cases when solid substances were dissolved, the per cent 

 indicated is a weight per cent. All solutions were of course 

 made up in sea-water. 



Wilson ('01) found that 2.5 per cent ether prevented the ap- 

 pearance of astral rays or spindles. I began my experiments by 

 determining the effect of such a concentration of ether on the 

 fertilized egg. 



June 22nd. Some eggs were fertilized at 9:42 a.m. and put into 2.5 

 per cent ether at 9:52 a.m. At 10:01 a.m. normal and etherized eggs 

 were centrifuged simultaneously, the high-speed handle being turned 

 30 times in 28 seconds. The normal eggs remained unstratified, the 

 etherized eggs showed a very evident stratification. Thus 2| per cent 

 ether has an antigelatinizing action. This concentration of ether pre- 

 vents spindle formation, although it does not otherwise harm the cell. 

 Higher concentrations of ether are injurious. Thus 4| per cent and 5 

 per cent ether produce a rapid coagulation, and Si per cent and 4 per 

 cent ether, although they at first tend to liquefy the cytoplasm, after 

 an hour or so coagulate it. 



Chloroform has a similar effect, as is borne out by the following 

 experiment: 



