178 Charles R. Stockard 



red spots. When thirteen or fourteen days old the embryos in the 

 1.33 m sugar solution resemble the normal embryos of only four or 

 five days. The eggs returned to sea-water after being twenty 

 hours in this solution begin hatching when fourteen days old. Only 

 in the o.i6f m solution of sugar in sea-water were the embryos 

 observed to hatch. The little fish seemed almost normal although 

 they swam peculiarly as their yolks seemed too large and heavy for 

 them to carry. 



Fig. 3 An embryo from a 0.88 m (30 per cent) sea-water sugar solution five days after fertilization, 

 showing the greatly contracted yolk and the dwarfed condition. X 175 diameters. 

 Fig. 4 A normal control embrj'o of the same age. X 17? diameters. 



The above effects are those expected to result from an increased 

 osmotic pressure, and they go to show that although these eggs are 

 without doubt very resistant to such pressure, it nevertheless exerts 

 an influence on their development. It will be noted by comparing 

 the effects of the sugar solutions in distilled water with those in sea- 

 water that a pressure more than double as strong in sea-water pro- 

 duces a much less injurious effect on the eggs. A not impossible 

 explanation of this peculiar fa'ct is that sugar in the fresh water 

 solutions be'comes inverted much more readily than in sea-water.* 

 The fresh water solutions of sugar were found to show an acid 

 reaction within a day or two after their preparation, and this acid 

 condition would cause the inversion of the cane sugar. On thef 



"* Dr. S. P. Bebee, of the Cornell University Medical College, has analyzed sugar solutions for me with 

 the following results: A 15 per cent distilled water solution of cane sugar becomes partly inverted if 

 allowed to stand for a day or so in the laboratory, while a 15 per cent sea-water solution kept under 

 similar conditions showed no trace of inversion after three days. 



