MACDOUGAL-^ACTION OF LIPOIDS IN GROWTH. 



47 



it more permeable to the potassium, the amount of endosmose by the 

 action of the sugar in the cell contents would have been increased. 

 It was lessened, in fact, suggesting that the saponin exercised some 

 influence on the condition of the wall or the plasmatic colloids. A 

 special series to test this matter was now arranged, as noted below: 



The presence of the saponin results in a diminution of endos- 

 mosis with either sugar or potassium chloride as the major con- 

 stituent of the cell-contents. Such a result has only one explanation, 

 that of increased permeability to both substances as a result of the 

 action of the saponin on the clay wall and the plasmatic layer. 



After the above readings had been made the cell which contained 

 potassium and was immersed in water was shifted to an immersion 

 in saponin 0.005M". Exosmosis resulted immediately, which would 

 be negative osmose, as the osmotic action of the salt solution would 

 be much greater than that of the dilute saponin without. The cells 

 containing water only were now filled with KCl 0.05 and immersed 

 in saponin o.oo5ilf . One gave 0.5 c.c, then showed exosmosis. The 

 other gave 2 c.c. and 1.8 c.c. on successive days. 



An untreated clay thimble was filled with the combined sugar and 

 saponin and set in saponin, with the result that an endosmosis of 

 I c.c. was measured in the first day. Another untreated thimble 

 filled with sugar in 5 per cent, solution gave 0.5 c.c. endosmose in 

 I day, which was below expectancy for these preparations. The cell 



