Ralph W. Webster 25 



same property of absorbing water may be doubted, as the soaps of the alkali-earth 

 metals are all insoluble and show no phenomena of solid solution. 



(6) The effect of the anion bound to the cation shows a marked variation in cases 

 of CI and NO3, on the one hand, and the SO4 group on the other. From previous 

 data we notice that the ions of CI, Br, I, and NO3 influence, to a very slight extent, 

 the absorption of fluid by a muscle, while those anions which precipitate calcium show 

 a marked positive effect. In fact, in solutions of salts of the polybasic acids, used in 

 our experiments, the anion was the all-powerful factor, while the cation plays an 

 indifferent role. In isosmotic solutions of the sulphates (the metal group being 

 indifferent) the absorption is between 4 and 10 per cent., agreeing, practically, with 

 the absorption under influence of NaCl. 



We must, therefore, assume that in this ion-proteid combination the anion, as well 

 as the cation, is attached to the proteid molecule, but at a different point of the 

 molecule. It thus appears that the group of salts, known pharmacologically as saline 

 cathartics, is not, in reality, an inhibitor of absorption, but is rather an accelerator of 

 this process. As the calcium salts seem to have a direct inhibiting effect on absorp- 

 tion by muscle, it may be possible that these cathartics may, by their precipitating 

 action on the calcium contained in the muscle, exert an accelerating effect. This con- 

 clusion is hardly plausible, inasmuch as we have the same amount of absorption under 

 the influence of NaCl. 



(c) The assumption, therefore, of a combination of both anion and cation with 

 the proteid of the muscle seems to be the most valid one. We must, however, admit 

 that in this combination the effects of the anion are in some cases more prominent, 

 while in others the action of the cation is the important factor. 



That cations and anions both combine with the proteid has been directly shown 

 by Pauli, Tangl and Bugarsky, Spiro, Atkinson, Stewart, and others. Our assumption 

 of "ion-proteids" is therefore made valid by direct experimentation. 



IV. INDEPENDENT ABSORPTION OF SALT AND WATER 



The question naturally arises in this discussion, whether the increase in weight 

 of a muscle immersed in a solution is due entirely to absorption of water or partly to 

 water and partly to dissolved substance. Hofmcister has definitely shown in his work 

 on absorption of solutions by gelatine disks, that an independent absorption of salt 

 and of water takes place. That is, the solution is not absorbed as such, but water is 

 absorbed up to a certain limit, depending on the concentration, while salt is taken up in 

 quantities approximately proportional to concentration. Our work was not planned to 

 show the dynamics of the absorption to any further extent than to prove the absorption of 

 water on the one hand, or, on the other, the absorption of the salt along with the water. 



It will be recalled that the sarcolemma is permeable to certain ions which have 

 been shown to actually enter the muscle and form compounds with the proteid (col- 

 loids) of the muscle. We should, therefore, expect to find by gravimetric methods 

 that salts had actually added to the original weight of the muscle. If we estimate the 



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