Kalph W. Webster 9 



molecular imbibition. Through these forces, he is led to believe, the absorption of 

 water and of salts is controlled, it being quite evident that the absorption of water 

 and salts goes on quite independently the one of the other. 



Van Bemmelen, in his work on absorption by colloids, has shown that inorganic 

 colloids, such as Si02, Fe(0H)3, etc., have quite a similarity to organic colloids. The 

 absorption of water and of salts from solutions is dependent on the nature of the sub- 

 stance in solution as well as on the concentration of this substance. Absorption by 

 inorganic colloids, he states, depends on several factors, (1) structure of colloid, (2) 

 modification brought about in this structure through gel-formation, heat, etc., (3) 

 vapor-tensiori (osmotic pressure) of fluid to be absorbed, (4) temperature, (5) kind 

 of solvent. Great interest attaches itself to his work on the conversion of a hydrosol 

 into a hydrogel. He declares that salts (with strong acids) of trivalent metals have 

 the strongest coagulating power, then follow in turn the salts of bivalent and univalent 

 elements. This fact has been elaborated by Hardy into the law that "the coagulating 

 power of salts of elements increases as the 2nd, 3rd .... power of the valence of 

 that element.' In this connection Hardy states that, in general, electrolytes have an 

 effect while non-electrolytes have none ; a statement quite in harmony with those made 

 by Loeb, Lingle, Moore, Mathews, and others concerning the action of electrolytes 

 and non-electrolytes on organic colloids. 



In order to test the conclusions of the various workers and to show, further, the 



action of various ions as well as the r6le of osmotic pressure in the phenomena of 



absorption of liquids by muscular tissue, this work was undertaken at the suggestion of 



Professor Loeb. 



IV. MATERIAL AND METHOD 



Owing to the fact that it is readily accessible, that any variations in its condition 

 may be easily controlled, and that experiments with it may be accurately carried out, 

 the gastrocnemius muscle of the frog was selected as the research material for these 

 experiments. The muscle is removed from the leg, cai-e being taken not to injure the 

 muscle substance, not to use for experimentation muscles which have been very active 

 previous to removal, and to exclude those muscles which show bruises or hemorrhagic 

 areas. After being carefully dried with sheets of filter-paper, the muscle is placed 

 between watch-glasses and accurately weighed. Thus weighed the muscle is placed 

 in a dish containing approximately 25 c.c, of the solution of the substance whose action 

 is under investigation. The concentration of the solutions varied within rather wide 

 limits, inasmuch as it seemed desirable to ascertain the effects of various concentra- 

 tions of the same substance, as well as the same concentration of various substances. 

 The working basis of the concentration was made that of | m NaCl, as this had been 

 previously shown by Miss Cooke to be isosmotic with the muscle -plasma. The con- 

 centrations of the various solutions were graded, starting with -f-m., following with 

 m, ^m, :^m, ^m, i\ra, and ending with ^^m, This range seemed necessary in order 

 to give ample scope to the study of hyper-, iso-, and hypo-tonic solutions. In the later 

 experiments only solutions isosmotic with |m NaCl were used, as it appeared possible, 



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