116 ISOTONIC COEFFICIENT. [CH. V 



Fig. 22 gives tracings of pieces of split Ricinus 

 hypocotyl before and after immersion. 



The upper row of tracings gives the form of the pieces 

 before being plaoed in the solutions, the lower row shows 

 the change of form produced by the immersion. The 

 numbers 010, 012, etc. give the strength of the KNO, 

 solution in which each was placed. 



Fig. 22, Exp. 148. 



It will be seen that the first two have increased in 

 curvature, while the last two have uncurled and the 

 middle piece (i.e. that in the 013 solution) remains 

 unchanged. Therefore 013 expresses the osmotic quality 

 of the cell sap in terms of KNOj. 



(149) Isotonic coefficient. 



The same experiment must be made with cane sugar, 

 using solutions 016, 018, 0*20, 0-22, 0-24. From the results 



