EXPERIMENTS WITH FROG S EGGS. 



retarded but more irregular than normal, and came to an end 

 before many divisions had been carried out. The details of the 

 results were as follows : 



35 



FIGS. 32-33. Segmentation of egg in lithium chloride and sodium chloride. 

 Rana palustris. 



FIGS. 34-35. Segmentation of egg in lithium chloride and magnesium chloride. 

 R.ina palustris. 



The eggs in the two-cell stage were put into the double solu- 

 tion. After two hours a normal looking two-cell stage was 

 present. After another two hours the cells had divided, and 

 were in the same condition two hours later, Fig. 32. The 

 egg shows little or no segmentation cavity. Other eggs have an 

 abnormally small segmentation cavity. After two hours more, 

 the upper cells have again divided, and the upper ends of the 

 lower cells also. After two hours more, the eggs appear to 

 be in the same condition, and this is also true for the next six 

 hours. Sections of these eggs show a tendency for the blasto- 

 meres to run together (Fig. 33), and each contains several nuclei. 

 After a further interval of eight hours, the cell-\valls have largely 

 disappeared on the surface. 



