274 T. H. MORGAN AND C. R. STOCK ARD. 



In a ten per cent, solution of cane sugar the blastopore may 

 develop, but in a thirteen per cent, solution only the later cleav- 

 age is reached. In a 5.5 per cent, solution of glucose the blasto- 

 pore may develop in an abnormal way, while in a 6.0 per cent, 

 solution only the late cleavage stage is reached. The results 

 show that the same effect is produced by the same osmotic pres- 

 sure of the two sugars. 



A double solution of LiCl 0.5 per cent, plus glucose 0.5, 0.7, 



and 1.0 per cent, gave the following results : 



LiCl 0.5 per cent, plus glucose 0.5 per cent., late segmentation. 

 LiCl 0.5 per cent, plus glucose 0.7 per cent., late segmentation. 

 LiCl 0.5 per cent, plus glucose I.cper cent., segmentation more abnormal. 



The action of LiCl 0.4 per cent, plus glucose 1.0, 2.0 and 2.5 

 per cent, was as follows : 



LiCl 0.4 per cent, plus glucose 1.0 per cent., very late segmentation: abnormal 



blastopore. 

 LiCl 0.4 per cent, plus glucose 2.0 per cent., late segmentation ; not so far. 

 LiCl 0.4 per cent, plus glucose 2.5 per cent., late segmentation. 



The results show that by adding amounts of glucose to a solu- 

 tion of LiCl, the development is stopped at a pressure higher 

 than that for LiCl alone, but less than that for glucose alone, 



Another similar experiment gave the same results. In a third 

 experiment with LiCl 0.4 per cent, plus glucose 0.5, 1.0, 1.5 and 

 2.0 per cent, the results were nearly the same as is shown below. 



LiCl 0.4 per cent, plus glucose 0.5 per cent., gastrulation normal, but delayed. 

 LiCl 0.4 per cent, plus glucose i.o per cent., barely gastrulating : abnormal. 

 LiCl 0.4 per cent, plus glucose 1.5 per cent., barely gastrulating : abnormal. 

 LiCl 0.4 per cent, plus glucose 2.0 per cent., late segmentation only. 



The upper limit for this combination is about LiCl 0.4 per 

 cent, plus glucose 2.0 per cent, with an osmotic pressure of 6.63, 

 which is above LiCl .65 (= 6.16), but lower than glucose 6.0 

 (=8.376). 



The results with NaCl plus glucose were as follows : In a solu- 

 tion of 0.5 NaCl plus glucose 1.0, 1.5, 2.0 and 3.0 per cent, the 

 late segmentation stages developed, but the yolk was injured. In 

 another experiment the results were more decisive. 



NaCl 0.5 per cent, plus glucose I.O per cent., circular blastopore above equator. 

 NaCl 0.5 per cent, plus glucose 1.5 per cent., late segmentation. 

 NaCl 0.5 per cent, plus glucose 2.0 per cent., dead in segmentation stages. 

 NaCl 0.5 per cent, plus glucose 3.0 per cent., not so late segmentation. 



