276 T. H. MORGAN AND C. R. STOCKARD. 



manner. The sugar solution was freshly prepared before start- 

 ing the experiments, and Heines' solution was used to test the 

 sugar to further assure ourselves of its purity and uninverted 

 condition. 



The 6 per cent, cane sugar solution delayed the rate of de- 

 velopment after about twenty hours, so that when forty-eight 

 hours old the eggs were far behind the control ; and although 

 neural folds and other indications of the embryo were present 

 the embryonic outline was usually shortened as an effect of the 

 delayed blastopore closure. The 8 per cent, solution gave much 

 more marked effects. After twenty-four hours abnormal gastrulae 

 were formed, though none became elongated or showed any in- 

 dication of embryo formation. Such a condition is similiar to 

 that described below for eggs in 4 and 5 per cent, solutions of 

 glucose and lsevulose ; the pressures of the 5 per cent, solutions 

 are, however, slightly more than that of the 8 per cent, cane 

 sugar. After fifty hours all of the eggs in the 8 per cent, solution 

 were dead. Cane sugar of 9 per cent, had much the same effect. 



Solutions of 10, 11, 12 and 12.5 per cent, cane sugar gave 

 rather uniform results. Development was delayed within ten 

 hours or less and usually stopped before gastrulation had com- 

 menced. In the 10 per cent, solutions, however, some eggs 

 formed very abnormal gastrulae of a rather uniform type, the up- 

 per dark or micromere portion of the egg had sunken in the lower 

 coarser cells suggesting somewhat in gross appearance an acorn 

 held in its saucer-like burr. It is of interest to note that such a 

 type of gastrula was also found in the 5 per cent, glucose and 

 laevulose solutions which exert approximately the same pressure 

 as the 10 per cent, cane sugar. 



The 13 and 15 per cent, solutions act much the same, the 

 weaker giving less marked effects than the stronger one. After 

 ten hours the eggs were much delayed, the white area had not 

 been encroached upon by the darker cells and was divided into 

 only six or eight large blastomeres. The eggs were all much 

 plasmolized and development after twenty-two hours in the 

 solution had progressed only about as far as control eggs of nine 

 or ten hours old. Late segmentation was reached, and the eggs 

 died in this condition after forty-five hours. 



