20 Absorpticn of Liquids by Animal Tissues 



results, that we must admit the permeability of the muscle membrane to the anion 

 as well as to the cation of the salts investigated. However, it must be said that the 

 effect of the anion seems to have no greater significance than that those anions pre- 

 cipitating Ca act much more readily than the others by disturbing the physiological 

 balance more quickly than do the anions CI, Br, I, NO3, etc. 



Concerning the permeability of the sarcolemma to non-electrolytes such as sugar, 

 urea, water, etc., we have little literature to draw from. The above mentioned authors 

 show that rhythmical contractions do not arise in solutions of non-electrolytes. How- 

 ever, from the absorption phenomena noted in case of cane sugar and urea we notice 

 that the sarcolemma is permeable to urea and not to cane-sugar solutions. 



Having shown the permeability inward of the sarcolemma for the various sub- 

 stances investigated, our next question seems to be, Is the sarcolemma permeable out- 

 ward to these same substances? It is a well-known fact that the red blood-corpuscles 

 of most animals contain more potassium than sodium while the serum of the same 

 animal contains these elements in the reverse relation. This same thing is noticed 

 in case of composition of muscle plasma. These facts seem to show that the corpuscles 

 and muscles are impermeable to the Na and K ions, else we should have an equilibrium 

 established between these ions on both sides of the membranes in question. The 

 work, previously mentioned, on red blood-corpuscles seems to show that the corpus- 

 cular membrane is impermeable to K, Na, Ca, sugar, etc., while it is permeable for 

 NH4CI, urea, etc. Our work on muscle shows that the sarcolemma is permeable for 

 Na, K, Ca, NH4, urea, etc., while it is impermeable to sugar. How account for these 

 variations? As we have seen above, differences in osmotic pressure were given as the 

 cause of the phenomena noted in red blood-corpuscles, while, in our work, these differ- 

 ences do not explain the effects of the various substances used. The answer to these 

 questions might be that in case of blood corpuscles we are dealing with a membrane 

 which is permeable in neither direction to certain ions, while in muscle we have to do 

 with a membrane permeable in both directions although the rate of diffusion is differ- 

 ent for each ion and is different in the two directions. That this latter statement is 

 correct may be readily seen from the following : The permeability inward of the 

 sarcolemma is evident from the experiments on rhythmical contractions of muscle. If 

 a muscle be placed in a solution of CaCl2, as we have seen, Ca and CI ions will enter 

 the muscle and will inhibit or restore rythmical contractions of a muscle according to 

 the state of a muscle previous to immersion in the solution. It can be definitely 

 shown that K and, possibly, Na ions have penetrated outward from the muscle by a 

 simple qualitative chemical test of the solution in which the muscle has been immersed. 

 By addition to this solution of hydrochlorplatinic acid, evaporation of the mixture 

 nearly to dryness, and then the addition of alcohol, we obtain the characteristic 

 reddish-yellow octohedra of K2PtCl6. It is to be remembered here that the detection 

 of Na in presence of K is not possible by this test as the Na2PtCl6 is soluble in the 

 alcohol used. We can, therefore, state definitely that K ions have penetrated outward 

 and that in all probability the Na ions have also done the same. Do Ca ions also 



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