500 EDWAED B. MEIGS 



nal weight in isotonic solutions of salts and sugars, gains weight 

 in hypotonic solutions, and loses weight in hypertonic solutions. 



The author has added some further evidence to that already 

 given by Overton for the view that both osmosis and a process 

 which may be called 'colloid swelling' play a part in the taking 

 up of fluid by muscle from salt and sugar solutions.'* It may be 

 shown that the behavior of frog's striated muscle when it is im- 

 mersed in distilled water or in isotonic sugar solution depends on 

 whether the tissue is 'living' or 'dead.' The hving muscle swells 

 in distilled water in such a manner as to suggest that osmosis 

 plays a large part in the process; the water intake is large in the 

 early stages and rapidly becomes less. The dead muscle, on the 

 other hand, tends to take up water less rapidly in the early stages 

 of its immersion than in the immediately succeeding ones. The 

 living muscle maintains its original weight for many hours in an 

 isotonic sugar solution while the dead muscle swells rapidly in 

 such a solution. 



Beutner has recently bee:i able to throw still further hght on 

 this subject. He has shown that the behavior of muscle immersed 

 in mixtures of salts with acids depends at first on the osmotic 

 pressure of the mixtures, while it later bears little or no relation 

 to osmotic pressure.^ 



If it be granted that the striated muscle fibers are surrounded 

 by membranes which are more permeable to water than to salts 

 and sugars in solution, a number of very important questions 

 regarding the nature of these membranes and regarding the 

 conditions which obtain within the muscle fibers remain to be 

 answered. The first of these questions is whether the mem- 

 branes are absolutely impermeable to salts and sugars, or whether 

 they must be regarded only as offering a considerable resistance 

 to their passage. 



So far as I am aware, no one has definitely advocated the view 

 that the muscle membranes are absolutely impermeable to salts 

 and sugars.^ All the evidence that exists on the subject at pres- 



* Meigs; American Jour. Physiol., 1910, vol. 26, p. 191. 

 5 Beutner; Biochemische Zeitschrift, 1912, Bd. 39, p. 280. 



^ For Overton's opinion on this subject, see Archiv fur die gesammte Physiologie, 

 1902, Bd. 92. pp. 382 and 383. 



