516 EDWARD B. MEIGS 



I have carried out a number of experiments in which the pro- 

 cedure was exactly the same as in those which have just been 

 described, except that at a certain point in the experiment the 

 tissue was transferred from Ringer to double strength Ringer 

 instead of to 50 per cent Ringer. Figures 5 and 6 give the results 

 of two such experiments. If figure 6 be compared with figure 4, 

 it will be seen that the striated niuscle loses weight in the hyper- 

 tonic Ringer very much as it gains weight in the hypotonic Ringer. 

 The curves in both cases are at first roughly exponential and then 

 tend to be straight lines, and the rapidity of loss in the double 

 strength Ringer is about equivalent to the rapidity of gain in the 

 half strength Ringer. In the smooth muscle the results are 

 widely different. The curves here show no indication of definite 

 mathematical character; the loss of weight during the second 

 interval after transference to the hypertonic solution is more rapid 

 than during the first interval. Perhaps, however, the most sur- 

 prising result is the difference between the rapidity of the loss 

 undergone by the smooth n .uscle in the hypertonic solution and 

 that of the gain undergone by the same tissue in the hypotonic 

 solution. In the first sixteen minutes after transfer to the hypo- 

 tonic solution, the tissue gains only 2 per cent of its original 

 weight while in the first sixteen minutes after transfer to the 

 hypertonic solution it loses 15 per cent. The same result has 

 been obtained in most of the experiments which I have carried 

 out. 



Experiments with solutions of single electrolytes. Overton and 

 other investigators have carried out experiments in which the 

 weight changes of frog' striated muscle in solutions of various 

 salts have been followed. These experiments have shown that 

 as a general rule the tissue tends to maintain its original weight 

 in solutions which have about the same osmotic pressure as a 

 0.7 per cent NaCl solution, to lose weight in solutions hypertonic 

 to this, and to gain weight in hypotonic solutions. The theory 

 that the striated muscle fibers are surrounded by semi-permeable 

 membranes rests partly on the results of such experiments. 



In 0.7 per cent NaCl solution smooth muscle gains in weight 

 at first rather more rapidly than in Ringer's solution, but this 



