III. 8 



CHEMICAL COMPOSITION 



133 



KI, SrBr 2 ), are all baneful, retarding and distorting- the embryo 

 to a greater or less extent. Ammonia, it may be noted, is fatal 

 at once. 



It has already been shown (p. 123) that the malformations 

 induced by sodium chloride in Amphibian embryos are to be 

 set down to some other property than the osmotic pressure 

 of the solution, and it is here only necessary to advert to 



Dextrose. 



FIG, 69. Cane-sugar (6-6 %). Two stages in the formation of the noto- 

 chord from the whole thickness of the roof of the archenteron in the Frog. 



Dextrose (34 %). Secondary degeneration of the gut roof and ventral 

 part of notochord. 



some of the more interesting effects occurring in particular 

 solutions. 



Although the more poisonous salts (e.g. Lil, CaCl 2 , SrBr 2 , 

 and others) inhibit altogether the formation of the blastoporic 

 fold, a cause which normally assists in its production the 

 proliferation of small cells in the roof of the segmentation 

 cavity may continue to operate, with the result that that roof 

 is thickened and thrown into puckers and folds. 



