PHYSIOLOGY OF SMOOTH AND STRIATED MUSCLE 541 



transferred from salt solutions to distilled water or to solutions of 

 non-electrolytes. Smooth muscle loses fluid in hypertonic Ringer 

 solution because the salts from this solution diffuse into the fibers 

 and render the colloids less capable of imbibing or of holding 

 water. 



From Experiments 34, 35, 65, 67, 69 and 73 it appears that 

 NaCl has a peculiarly strong effect in lessening the power of the 

 smooth muscle colloids to absorb and hold water; that NaC2H302 

 has less effect in this direction; K2HPO4, still less; and KCl, 

 much less than any of the other three. Experiments 7, 33, 57 

 and 59 indicate that the smooth muscle colloids show very little 

 increase in their tendency to absorb water until after they have 

 lost a large proportion of their NaCl. In Experiment 59 the 

 muscle had lost more than 40 per cent of its NaCl, yet had in- 

 creased in weight only 0.07 per cent. In Experiments 33 and 57 

 small pieces of muscle which had already shown a marked tend- 

 ency to gain weight in Ringer's solution, were only -18.1 per cent 

 and 18.7 per cent heavier than originally after nineteen and 

 twenty hours' immersion in half strength Ringer respectively. 

 Experiments 9, 19, 27 and 53 show that pieces of smooth muscle 

 often gain weight more than this in Ringer's solution. In Experi- 

 ment 7, a small piece of muscle gained only 43.6 per cent in the 

 course of twenty-three hours' immersion in a 0.2 per cent NaCl 

 solution. This result is to be contrasted with those of Experi- 

 ments 76 and 13 in which pieces of muscle gained 82 per cent and 

 144 per cent of their original weights in 3.95 per cent dextrose 

 and distilled water respectively. 



A consideration of Experiments 3, 13, 15, 46, 60, 61, 76 and 79 

 shows that non-electrolytes have an effect in inhibiting the tend- 

 ency of the smooth muscle colloids to absorb water, particularly 

 in the presence of small amounts of electrolytes. It is impossible 

 to understand why the muscle of Experiment 61 should swell so 

 little in the mixture of sugar solution with Ringer, unless the sugar, 

 as well as the electrolytes of the mixture, has an effect in inhibiting 

 the colloids from swelling. Experiments 3, 13, 15, 46, 76 and 79 

 show how much more rapidly and to how much greater extent 

 smooth muscle swells in distilled water than in sugar solutions. 



