MACDOUGAL^ACTION OF LIPOIDS IN GROWTH. 



41 



size of the pore or the composition of the wall. The repetition of 

 the tests with calcium chloride at o.ooiM as an immersion fluid on a 

 clay cell filled with water gave an exudation of 1.3 to 1.6 daily for 

 twenty days. At the end of this time the external liquid was replaced 

 T^y one more concentrated at o.oiM. The rate rose slightly during 

 the first day, then fell away to 0.2 c.c. on the fifth day. 



Another interesting case was that in which a clay cell containing 

 sodium at o.oiilf was set in a calcium solution 0.00 iM. The initial 

 action was a negative osmose resulting in the loss of water from the 

 stronger sodium to the weaker calcium solution outside the cell during 

 the first 24 hours. The action was now reversed and endosmosis 

 began at the rate of 0.2 c.c. daily, which rose to 1.4 c.c. daily on the 

 fourteenth day, after which the rate fell off. Replacement of the 

 immersion solution with a more concentrated calcium solution at 

 0.0 1 M did not alter this process, as the rate continued to decrease to 

 0.2 c.c. on the tenth day. 



After such measurements had been made of the porosity of the 

 clay walls, lining layers of various mixtures of biocolloids were placed 

 in them and their absorption capacity measured by the amount of 

 water delivered by the outlet tube. 



The examples given below are sets selected at random from a 

 large number in which no radical departure from the average behavior 

 was found. Unless otherwise stated the cells were immersed in 

 water, and the cell contents were at 0.0 iM. Endosmose measured 

 as excretion is given below in c.c. 



A special set of cells for testing the comparative effects of sodium 

 and potassium chlorides at o.oiM with a plasma of agar-gelatine- 

 potassium oleate was operated with results as follows : 



