BOOKS AND CURRENT LITERATURE 



Permeability and Antagonism. — Osterhout is continuing his 

 earlier work upon antagonism and has recently published several articles 

 on the measurement of protoplasmic permeability with reference to 

 various salt solutions and the antagonistic effects of certain pairs of 

 salts on each other. An attempt is made to put the whole matter on a 

 quantitative basis by using exact electric measurements.^ As hereto- 

 fore, he employs small disks (13 mm. in diameter) cut from Laminaria 

 fronds, these disks being placed together so as to form a cylinder. 

 Through this cylinder of tissue an electric current is passed from end 

 to end and the resistance is measured. The conductance (reciprocal 

 of the resistance) is taken as a measure of protoplasmic permeability. 

 By treating the cylinder of tissue with various salt solutions it is found 

 that one class of substances (those that contain monovalent kations, 

 except H) increases permeability while another class (those that con- 

 tain bivalent or trivalent kations) decrease it. In the first class be- 

 long the chlorides of K, Cs, Kb, Li, NH4, also other salts such as the 

 bromide, iodide, sulphate and acetate of Na. Examples of the second 

 class are chlorides of Ca, Ba, Sr, nitrates of La, Ce, Y, Th and sulphates 

 of Fe and Al. According to his hypothesis,^ substances in one class 

 should have an antagonistic action on those of the other, and the 

 degree of antagonism should depend on the extent to which the one 

 substance increases and the other decreases permeability. NaCl in- 

 creases permeability while CaCU decreases it, hence these substances 

 vaQ.y be expected to antagonize each other with respect to permeability 

 changes and this is found to be true in actual experiment. A number 

 of salts were thus studied and it appears that those with bivalent and 

 trivalent kations' act in a greater or less degree, like CaCU, decreasing 

 permeability. 



The question as to whether the changes in permeability thus shown 



1 Osterhout, W. J. V., The permeability of protoplasm to ions and the theory 

 of antagonism. Science n. s. 35: 112-115. 1915. 



^Osterhout, W. J. V., On the nature of antagonism. Science n. s. 41:255- 

 256. 1915. 



' Osterhout, W. .J. V., On the decrease of permeability due to certain bivalent 

 kations. Bot. Gaz. 59: 317-.330. 1915. Idem, The effect of some trivalent and 

 tetravalent kations on permeability. Bot. Gaz. 59:464-473. 1915. 



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