THE PHYSIOLOGY OF REGENERATION 



327 



von der Entwicklung des Keimes bis zur Hohe des freien Wachs- 

 thums." 



Davenport's work was followed by a thorough and very labori- 

 ous investigation by Schaper ('02), who laid particular stress 

 upon the distinction between intracellular and intercellular growth, 

 and the relation of the imbibition of water to the intercellular 

 mode of growth. His results, while including a wider range of 

 stages, are substantially the same as those of Davenport. 



Day-i. 



70 



Fig. 4 Graphic representation showing the percentage of water in frog embryos 

 from one to eighty-four days after hatching. From Davenport, ('97, p. 77, fig. 3) 

 Proceedings of the Boston Society of Natural History, vol. 28, 1897, by permission 

 of the Society. 



Bialaszewicz ('08), studying this problem quite recently, has 

 analyzed the water content in frog's eggs not only after hatching 

 but likewise during the segmentation stages. His conclusion 

 (p. 819) is that "das Wachstum der Froschembryonen wahrend 

 der Entwicklung innerhalb des Dottermembran ausschliesslich 

 auf der Zunahme der Menge des durch den Organismus aus der 

 Umgebung aufgenommenen Wassers beruht." This investigation 

 ends the series of experiments which have established the fact that 

 the frog embryo from the earliest stages of development grows 

 through imbibition of water from the surrounding medium. 



The results of all these observers (Bezold, Davenport, Schaper, 

 Bialaszewicz), covering, as they do, longer or shorter periods and 



