512 EDWARD B. MEIGS 



A number of experiments have- been carried out with the view 

 of determining the factors which cause the tissues of some frogs 

 to take up more fluid from Ringer's solution than those of others. 

 It has been found to be a general rule that the tissues of the larger 

 frogs of a species tend to take up more fluid than those of the 

 smaller ones. This rule has nothing to do with the actual size 

 of the tissues used. A 'small' bull-frog may be larger than a 

 'large' leopard frog, but the stomach muscle and sartorius of the 

 former tend to take up less fluid from Ringer's solution than those 

 of the latter. The rule is of interest in connection with the now 

 well known fact that the tissues of the older (and larger) members 

 of a species tend to contain more solids and less water than those 

 of the younger members. ^^ Experiments 26, 27, 30 and 31 show 

 the variations in the manner in which the tissues of the different 

 sized frogs of a species behave in Ringer's solution. 



There are a number of other factors besides the age and size of 

 a frog which have an influence on the amount of fluid which its 

 stomach muscle will take up from Ringer's solution. The effects 

 of temperature are, perhaps, as striking as those of any other 

 influence. Figure 2 gives a comparison of the amount of fluid 

 taken up from Ringer's solution by two pieces of muscle from the 

 stomach of the same leopard frog which were kept at about 0.5°C. 

 and at room temperature respectively. The piece of muscle kept 

 at room temperature took up more than twice as much fluid as 

 the other. 



Experiments with diluted and concentrated Ringer^s solution. 

 Both the striated and smooth muscle of the frog remain alive for 

 many hours in double strength Ringer and in half strength 

 Ringer, i** and the changes of weight undergone by the two tissues 

 when transferred from Ringer to one or the other of these solu- 

 tions are very interesting. They add still further evidence to 

 that which has just been presented for the view that the surfaces 



18 See V. Bezold, Zeitschrift fiir wissenschaftliche Zoologie, 1857, Bd. 8, p. 487; 

 and Donaldson, Jour. Comp. Neur., 1910, vol. 20, p. 119. 



" By 'half strength Ringer' is meant a Ringer solution diluted with its own vol- 

 ume of distilled water, and by 'double strength Ringer' a solution in which all the 

 salts have double the concentration that they have in ordinary Ringer. 



