Distentive Agencies in Growth of Cell. 105 



The hydration reactions of living cell masses, of dried tissues 

 and of plates of colloids simulating the composition of living 

 matter having been determined, attention was next turned to 

 experiments which might afford a means of estimation of the 

 action of such material in the vacuolated cell. In brief it was 

 found necessary to devise a new or improved form of a little used 

 type of artificial cell. It was seen that such a device should be 

 one in which the character of the wall might be changed, the 

 plasma represented by various jellies with consequent variations 

 in the contact zones (phase boundaries), and furthermore that 

 such a cell could be subjected to a range of solutions, externally 

 and internally comparable to those of the living cell. Such a cell 

 consists essentially of a capsule of a gel enclosed in walls of varying 

 porosity and other mechanical characters. To facilitate deter- 

 minations of action the capsule must be fitted with an osmometer 

 head for measurement of volume or pressure. The experiments 

 which have been made to this date have been with cells in which 

 agar, gelatine and various mixtures of these with potassium oleate, 

 calcium oleate, lecithin and other substances have been used as 

 the "plasmatic" layer and the outer wall was represented by 

 platinum gauze, Whatman's double thickness filter- or extraction- 

 thimbles, wooden cups, and by clay cups such as are used in the 

 Livingston atmometer. The ranges of conditions offered for the 

 study of absorption and of osmose are fairly equivalent to those 

 of the living cell. 



If we now take such a cell and set it in operation to ascertain 

 what may happen when the vacuoles begin to appear by syneresis 

 in the protoplasm, using for example one in which the jelly forms 

 a layer about 3 mm. in thickness on the inner side of the wall with 

 a cell content of 30 to 40 c.c. we may get what may be taken to be 

 the initial action in such a case by filling it with water and setting 

 it in water. The first thing to occur in such a case will be the 

 hydration of the jelly to a point approaching its maximum. 

 Coincidently the solution or dispersion of material from the inner 

 surface of the layer begins in a manner which should be practically 

 identical with that which ensues with the enlargement of the 

 vacuoles. The action of these free particles of colloidal material 

 results in a mounting osmose which measured by the exudation 



