26 Absorption of Liquids by Animal Tissues 



dry weight of one gastrocnemius by placing it, as soon as it is removed from the body, 

 in a dessicator containing sulphuric acid, for twenty-four hours, while the dry weight 

 of the other gastrocnemius of the frog is estimated after it had been in a solution of 

 2-Lm Nag SO 4 for twenty-four hours, we should expect the dry weight of these two mus- 

 cles to show the same slight variations noted in the original muscles, provided the 

 increase in weight of the second muscle was due entirely to taking up of water. If an 

 absorption of salt occurred in the second muscle, this absorption would of course be 

 evident in an increase of the dry weight of the second over the first muscle. Such 

 experiments were carried out with several muscles, the result being quite positive in 

 all cases. From the following data the absorption of salt may be readily observed: 



Wt. of orig. muscles Wt. after being in Weight after drying Orig. difference Final difference 



in grams sol. 24 hrs. 36 hrs. in wt. in wt. 



2.313 3.42 .6347 .0189 .0315 



2.2941 .6032 



The original difference in weight is markedly less, relatively speaking, than the 

 final difference. Apparently, an absorption of .0126 grams of salt has taken place. It 

 seems very plausible to conclude, from this composite experiment, that absorption of 

 both water and salt has occurred but that a much larger absorption (98 per cent.) of 

 water than of salt has taken place. If the solvent action of the solution upon the pro- 

 teid, as well as the outward passage of Ca and other ions from the muscle, be 

 remembered, it may be readily understood why the increase in dry weight is not 

 more marked. It may be argued that the time of drying would necessarily influence 

 the amount of water given off by the muscle when in the dessicator and that this 

 slight increase was due to unequal time of evaporation. The experiment was con- 

 tinued for some time, daily observations being made, until the weights of the two 

 groups of muscles remained constant for two consecutive days. We may in this case 

 assume that the difference in weight, if any exists, is due to the taking up of salt by 

 muscles immersed in the salt solution. The results follow: 



Original weight 



2.313 

 2.2941 



The difference has not disappeared on more complete drying. An interesting 

 observation was brought out in these experiments. If we calculate, from figures given by 

 Danilewsky, the amount of water in the above muscles, we find that the weight obtained 

 by deducting the amount of water from the weight of the original muscle is larger than 

 the weight obtained in our drying experiment. It is therefore clearly evident that 

 Danilewsky's figures for per cent, of water in muscl are low or that in these experi- 

 ments some abnormally watery muscles were used. In the following data these points 

 may be noted, assuming, according to Danilewsky, 78.8 per cent. HgO in muscle: 



Weight after deducting 11,0 Weight after drying 



.4900 .4702 



.4861 .4361 



128 



