1908] Ritter-Bcriley— Weight of Developing Eggs. 5 



lieve it is inducing us either to overlook entirely or to view as 

 insignificant vast multitudes of seemingly detached facts that 

 mighl lie measured by balance and rule, mathematically treated, 

 and so reduced to "law and order" and thus shown to be sig- 

 nificant facts in the life of the organism as a whole. 



PART II. 

 PRACTICABILITY OF THE DETERMINATIONS. 



BY 



S. E. Bailey. 



The variation in the weight of eggs during segmentation and 

 development has for some time been a subject of more or less 

 interest and speculation. With a view to gaining more light on 

 this subject, Professor Ritter asked me to try to make some direct 

 determinations of this variation while I was at the San Diego 

 laboratory this summer. As will be seen, my results are not in 

 any way complete. I have simply made it obvious that experi- 

 ments of this nature are practicable — that the technique of serial 

 weighings of developing eggs is. for some kinds of eggs at least. 

 a comparatively simple matter. 



.My prohlem was in substance this: 1. To find some hardy eggs 

 which could be enseminati d and allowed to develop under known 

 conditions. 2. To find some method by which these eggs could 

 he weighed accurately from time to time. To accomplish these 

 objects various precautions were necessary. The eggs could not 

 be dried before weighing and so had to be weighed in water. At 

 first I experimented with the eggs of the ascidian Ciona intes- 

 tinalis, and then with those of the starfish Asterias tuberculoid. 

 Great difficulty was encountered in handling them. They were 

 too small and numerous to be counted easily and quietly, and one 

 could never feel sure that some had not been lost from weighing 

 to weighing. When kept in small silk nets, the eggs, net and all 

 being weighed, other difficulties were encountered. The nets 

 alone varied in weight from gradually soaking up water and ac- 

 cumulating dirt, and besides some eggs, not getting properly 



