SECT. 6] 



OF THE EMBRYO 



885 



older an individual the more easily can flocculation of the proteins 

 of its tissue juice be brought about. Thus the "Pressaft" of frog's 

 eggs required 2-66 c.c. of 96 per cent, alcohol for flocculation, while 

 that of lo-year old frogs required only 0-9 c.c. This phenomenon 

 was related, he thought, to the isoelectric point of the cell-protein. 

 Coherence, degree of condensation, hysteresis (passage from sol state 

 to gel state) with many other concepts all intimately associated with 



t: 70 



SchaperO Org. subs. 

 • Ash 

 ® Water 

 Davenport- Q Water 



Bialascewics Water 

 raure-Fremiet\<a Water 

 &, Dragoiu 



Williams © WaberRanaSilv. 

 '♦ Bufo lenbig. 



5 

 Years 



decreasing water-content, form the components of Ruzicka's general 

 theory. 



In spite of this agreement, however, some facts had been known 

 for a long time which seemed to oppose the introduction of a 

 general law of decreasing water-content. The work of Davenport; 

 Schaper; Faure-Fremiet & Dragoiu; and Bialascewicz on the early 

 stages of amphibian development seems at first sight to be in contra- 

 diction with it, for, as Fig. 230 shows, the water-content rises steadily 

 until about a week after hatching. Kaufmann, again, showed that 

 salamander larvae cut out of the uterus took up much moisture when 



