EFFECT OF EXTRACTS UPON DEVELOPING EGGS. 



esting as well as worth-while to use extracts made up in solvents 

 other than sea water. Experiments made with such extracts 

 should be of use as a check upon the other experiments. Cham- 

 bers has contended that when a cell is broken into fragments by 

 mechanical means, the small pieces, because of surface tension, 

 usually become spherical in shape, and form a new surface film. 

 Perhaps, then, by breaking down such a possible film by the use 

 of solvents other than water, more of the " formative stuffs " 

 might go into solution. 



Series 47. 



The extract in this experiment was made by placing the crushed 

 embryos, motile blastulse, in faintly acidified distilled water. The 

 extract was allowed to stand for twelve hours before it was used. 

 The acidified water was made by adding four drops of glacial 

 acetic acid to 100 c.c. of distilled water. 



The controls were, of course, made by adding equal quantities 

 of the acidified water to the sea water when certain quantities of 

 extract were used in the cultures. 



TABLE VII. 



Later Development and Fate. Development in the cultures and 

 controls was very nearly parallel until the blastula stage was 

 reached. At this point, however, a very decided retardation in 

 all the cultures containing extract was noted. 



C was only very slightly retarded, however, at the blastula 

 stage, and reached the pluteus stage very shortly after C '. 



