ALTERATIONS IN WATER CONTENT 



467 



as the result of endosmosis (Fig. 45). Plant growth is con- 

 spicuously associated with turgor, and depends in great measure on 

 the amount of water taken up. Another and more plausible 

 explanation may be given of tlie swelling of plant tissues. In 

 Chap. VIII., p. 97, Table XV^II., we mentioned tiie power of 

 colloids to imbibe and compress water. It is extremely probable 

 that plant turgor may be due to this imbibition, initiated by some 

 alteration in the hydrogen ion concentration of the tissue. 



It has been definitely proved that animal growth is accompanied 

 bj' alteration in water content as shown in Tables LXXX. and 

 LXXXI. 



TABLE LXXX 

 Water Content of Human Embryo (FEHUNti) 



Water Content of Frog Embryo. (D.wenport.) 



TABLE LXXXI 



Percentages of Free and Bound Water in Animal 

 Tissues at Certain Ages (From Thoenes) 



30—2 



