25l> STUDIES IN GENERAL PHYSIOLOGY 



was the same in the plasmolyzed and in the normal 



At 11 o'clock I brought a second lot of eggs back from 

 the concentrated solution into normal sea-water. These eggs 

 did not show the slightest trace of segmentation. At 11:22 

 the eggs began to segment, but in hardly any case did the 

 eggs divide into two, but nearly all of them segmented into 

 more cleavage spheres at once. The number and size of the 

 cleavage spheres were not quite regular. There were mostly 

 about four spheres in one egg; sometimes, however, five to 

 eight. The size of the single cleavage spheres of the same 

 egg varied, the smallest spheres being about the size of a 

 cleavage sphere of the eight-cell stage, the largest that of a 

 two-cell stage. At 11:44 the first segmentation was finished, 

 and from now on the segmentation was perfectly regular. 

 At 11:40 the normal eggs were in the eight-cell stage. 



At 2:40 I brought another lot of eggs from the concen- 

 trated solution back into normal sea-water. Not one egg 

 showed segmentation. At 2:50 the segmentation began. 

 Just as in the 11 o'clock lot, hardly one egg segmented into 

 two cleavage spheres. But while most of the eggs of the 11 

 o'clock lot segmented into from four to eight cells, most of 

 the eggs segmented now into from eight to sixteen cleavage 

 spheres at once. The number and size of the cleavage 

 spheres varied again in the different eggs, but the striking 

 feature this time was the prevalence of cleavage spheres of 

 the size of the sixteen-cell stage. The normal eggs by this 

 time were into the morula stage. At 4:05 another lot of 

 eggs was brought back from the concentrated solution into 

 normal sea-water. Not one egg had segmented. Twenty 

 minutes later, however, nearly all the eggs were in cleavage. 

 But this time they did not divide into sixteen, but into many 

 more segments at once. I think that most of the eggs 

 showed about thirty cleavage spheres. Of course, in this 



