Kalph W. Webster 21 



penetrate outward? If a muscle be placed in a solution of Na2S04 rhythmical con- 

 tractions are, as mentioned above, observed at once. If the muscle be allowed to 

 remain in these solutions 12 hours a slight opalescence is observed which becomes 

 more marked at the end of 24 hours and may even pass into a distinct precipitate. On 

 examination of this precipitate by ordinary qualitative methods, Ca was, unmistakably, 

 shown by its characteristic oxalate. There can be no doubt, therefore, of the perme- 

 ability outward of the sarcolemma in case of Ca ions. This latter reaction must not be 

 confused with another which is observed in practically all of the salt solutions used, 

 although it was more marked in case of the solutions whose anion precipitated Ca. 

 The reaction in question is as follows : If a muscle be placed in certain salt solutions, 

 preferably the sulphate or oxalate of alkali metals, there will be observed in 18 

 hours a decided opalescence. This turbidity is not all due to the precipitation of Ca 

 salts as is seen from the experiment. The opalescent solution is heated to 65-75° C 

 for a few minutes, when a distinct coagulum appears which resembles that of white of 

 egg. The solution has a strong proteid odor and shows a distinct froth on its surface. 

 Tested with CUSO4 and KOH a distinct violet coloration is noted. This seemed to 

 point to the presence of proteid matter in the solution. In order to confirm this 

 assumption it seemed necessary only to test for carbon and nitrogen. By the ordinary 

 organic methods of examination both these elements were detected, showing con- 

 clusively the presence of proteid. Here we have, evidently, to do with the solvent 

 action of the salt solution upon the proteid matter of the muscle. We are, however, 

 not in a position to give the origin of this proteid. Two possibilities present them- 

 selves for consideration. In the first place we may have a simple solvent action of 

 the salt solution upon the surface of the muscle. Secondly, we might conceive of some 

 combination of the proteid, within the sarcolemma, with the salt, which combination is 

 diffusible. The first possibility seems much more plausible but cannot be absolutely 

 proven by these experiments. 



The sarcolemma of the muscle is, therefore, permeable to the ions under investiga- 

 tion. However, it is readily seen from the previous points that the rate of movement 

 of the ions is different in each direction. Whereas, for instance, the inward penetra- 

 bility of the Na ion may be definitely shown within a few minutes, the outward pene- 

 trability may not be detected for several hours. Moreover, we know that the rate of 

 diffusion of Ca ion is much slower than that of the Na and approximately the same 

 as the K ion because, according to Graham's law of diffusion of gases, we should 

 expect the rate of diffusion to be inversely proportional to the square root of the density 

 of a solution. Reid has shown that the rate of osmosis through the skin of a frog is 

 different in each direction. We are, hence, justified in our assumption here, that the 

 sarcolemma of the muscle is permeable in both directions to certain ions and that the 

 rate of diffusion is different in each direction being much faster inward than outward. 

 In this passage of ions into and out from a muscle we have many more ions entering 

 the muscle than leaving during the same interval of time owing to the factors (1) of 

 rate of migration of ion and (2) direction of migration. Just how far these assump- 



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