RALPH S. LILLIE 789 



ably in part determined by similar conditions, although factors 

 peculiar to suspensoid systems no doubt also enter in these cases. 

 The properties of soaps, which are at once soluble in water and in 

 many organic solvents, and which are consequently highly surface- 

 active at water lipin interfaces, are probably of fundamental impor- 

 tance in protoplasmic activities. It is noteworthy that the water- 

 combining properties of tissues and cells are influenced by salts in a 

 manner consistent with the hypothesis that soaps or compounds 

 with similar solubilities determine the manner in which the bound 

 water (Overton's ''Quellungswasser")^ is held in the protoplasm. 

 Many years ago Loeb^ called attention to the parallel between the 

 absorption of water by muscle immersed in isotonic solutions of 

 different salts of alkali and alkali earth metals, and by the soaps 

 of the same metals; thus, the muscle absorbed much m.ore water in 

 isotonic KCl solution than in NaCl, while in isotonic CaCl2 it lost 

 water; when the corresponding soaps are immersed in water a similar 

 order of relative absorption is seen, K soaps (soft soaps) swelling more 

 rapidly than Na soaps, while the water-insoluble Ca soaps do not 

 take up water. Swelling and loss of consistency or turgor in plant 

 tissues immersed in pure NaCl solution are well known phenomena, 

 which have recently been investigated in great detail by Hansteen;^ 

 the disintegration and loosening of the intercellular coherence which 

 he describes as occurring under these conditions are prevented by 

 the presence of small quantities of calcium salts. Hansteen calls 

 attention to the earlier work of Mangini*^ on the role of the pectin 

 com.pounds in the interstitial substance or middle lamella of plant 

 tissues; the cementing properties of this layer are, according to 

 Mangin, dependent on the presence of an insoluble Ca compound 

 which he calls "Ca pectinate." In the presence of NaCl solution 

 free from Ca this layer becomes soluble and absorbs water and the 

 cells fall apart. Herbst's^^ observations on the loss of coherence of 

 of the blastomeres of sea-urchin eggs in Ca-free sea water probably 



"^ Overton, E., Arch. ges. Physiol, 1902, xcii, 115. 



^Loeb, J., Arch. ges. Physiol, 1899, Ixxv, 303. 



9 Hansteen, B., Jahrb. wiss. Bol, 1910, xlvii, 289; 1913-14, liii, 536. 

 ^^ Mangin, L., /. Bol, 1893 (cited from Hansteen). 

 " Herbst, C, Arch. Entwcklngsmechn., 1900, ix, 424. 



