io6 



Scientific Proceedings (119). 



from the outlet of the cell reaches its maximum between 75 and 

 100 hours at 15 0 C, at about 3.5 to 4 c.c. daily and, when measured 

 in terms of pressure set up by a cell lined with agar the magnitudes 

 are in a range not far from those given for gum acacia. This 

 secretion or exudation was found to continue for as long as 70 or 

 80 days in cells with a plasmatic lining of a mixture of agar, 

 gelatine and potassium oleate, during which time the total excre- 

 tion would amount to two and a half times that of the capacity of 

 the cell, that is about 75 or 80 c.c. The dispersion and osmotic 

 action of the plasmatic colloids in the vacuoles as illustrated must 

 be recognized as one of the initial factors in the distention and 

 turgidity of the cell. Diffusion of sugars and their decomposition 

 products, and of amino-compounds of various kinds into the vacu- 

 ole, must also ensue from a constantly renewed supply furnished by 

 the metabolic activity of the protoplasm. Salts included in the 

 plasma must also be diffused into the vacuolar liquid, and it is to 

 electrolytes that Pfeffer and others attribute as much as sixty per 

 cent, of the total osmotic capacity of the cell, which in the higher 

 plants shows a potential from 3 to as high as 150 atmospheres as 

 determined by J. A. Harris and others using cryoscopic and 

 plasmolytic methods. When it is realized that the partial pres- 

 sures which must be attributed to the electrolytes are much higher 

 than those which are ordinarily found in soil solutions or in media 

 in which simple organisms live the manner in which the higher 

 concentrations are accumulated in the cell becomes as much of a 

 problem as that offered by glandular action in the body of the 

 animal. 



Some measurements of cumulative action in building up tur- 

 gidity have been made, in which it was shown that a cell mass 

 which might be plasmolyzed at a certain high concentration if 

 first immersed in a series at lower concentrations might be led up 

 to endurance of this concentration without loss of tugidity. A 

 similar action may be demonstrated by the artificial cell described 

 above. When lined with an agar-gelatine-potassium oleate mix- 

 ture it shows a tonicity of about 0.00 M. potassium chloride, 

 showing no positive action when filled with water and immersed in 

 a concentration above this. If however it is first allowed to get 

 into full action in the above concentration it may then by small 



