Experiments on the Early Development of the 

 Amphibian Embryo 



under the influence of Ringer^) and salt solutions. 



By 



Chas. B. Wilson. 



With plate X and XI. 



Eingegangen am 1. Juli 1897. 



Many experiments have recently been made upon the physiology 

 of the development of various eggs in order to arrive at a better 

 -understanding of the nature of the process, and to determine, as far 

 as possible, what forces are concerned in it. 



For this purpose eggs have been subjected to the action of 

 various drugs; they have been exposed to temperatures abnormally 

 high or low, and have been reared under other unfavorable con- 

 ditions. By a comparison of these investigations with those pursued 

 under normal conditions several interesting and important results 

 have been obtained, which throw considerable light on the phenomena 

 of early development and cleavage. 



But in almost every instance the experiments were performed 

 upon the eggs of a single species, which were fertilized artificially 

 and placed in the solution or subjected to the abnormal conditions 

 before they had begun to segment. The results, therefore, have 

 been somewhat limited, and it has been difficult to compare them, 

 owing to differences in the conditions under which they were ob- 

 tained. In actual life the young embryos are more apt to meet 

 changes in their environment during later periods of growth than 

 to find themselves at the beginning under abnormal conditions which 

 afterward remain unchanged. 



1) For composition of Ringer solution see foot-note on pag. 627. 



