A COMPARISON OF PERMEABILITY IN PLANT AND 

 ANIMAL CELLS. 



By W. J. V. OSTERHOUT. 



{From the Laboratory of Plant Physiology, Harvard University, Cambridge^ 

 (Received for publication, January 9, 1919.) 



In a study of the fundamental characteristics of protoplasm it is 

 desirable to compare the behavior of plants and animals under condi- 

 tions which are as similar as possible. The experiments here de- 

 scribed were undertaken from this point of view. Their object was 

 to discover whether the behavior of animals and plants is essentially 

 similar with regard to certain aspects of permeability, injury, recovery, 

 and death. 



The method consisted in measuring the electrical conductivity of 

 the tissues. Under the conditions of the experiment the electrical 

 conductivity of the tissue may be regarded as a measure of its permea- 

 bility to ions. 



The plant chiefly employed was Laminaria, although other material 

 was used for comparison. ^ The tissue was cut into disks and packed 

 together to form a cylinder whose electrical resistance was measured 

 as previously described. ^ 



The animal tissue used for comparison was the skin of the frog 

 {Rana pipiens), taken from the animal immediately after killing^ and 

 placed at once in the apparatus for measuring electrical resistance. 

 Inasmuch as the skin has not sufficient mechanical rigidity to permit 

 the same kind of manipulation which is possible in Laminaria, it was 

 necessary to fasten each piece between two thin hard rubber disks (or 

 between a rubber disk and one of thin celluloid), the disks being tied 

 together by means of projections at the edges and the space between 



^ Osterhout, W. J. V., /. Gen. Physiol., 1918-19, i, 299. 

 2 Osterhout, W. J. V., /. Biol. Chem., 1918, xxxvi, 557. 



^ The animals were killed by decapitation. The use of anesthetics must be 

 avoided as they may injure the skin. 



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