EQUILIBRATIONS IN PARTS OF ORGANISMS 



163 



No way is known of rendering the separated muscle like the intact 

 muscle in respect to volume adjustments. 



Ingrained in investigators is the desire to say : the changes of 

 volume in blood and in muscle may all be predicted, for the force of 

 osmotic pressure, which is concerned here, produces movements of 

 water proportional to the gradient of concentration of solutes. 

 Such a hypothesis appears valuable, for in part the data agree with 

 it. But the data do not allow the conclusion that only osmotic pres- 

 sure is concerned. Even after the initial 0.2 hour, many other 

 pressures or forces may be changing along with the volume of the 



20 



c 



y 



o 



10 



?30 



5econd half hour 



+Z0 



■ZO -10 ^\0 



Total Water Load 

 Fig. 99. Eate of water exchange (% of BoAour) in relation to total water load 

 (% of Bo). Isolated thighs of Rana pipiens, immersed in Einger's solution at 21° C. 

 Zero load represents the thigh's weight when in the frog that is in water balance. Data 

 (of Wolf, '40b) taken from figure 98. 



tissue, and any or all of these might give a like result. In general, 

 one scientist may get a thrill at finding the data in agreement with 

 some prediction, another at finding the unpredicted. Therefore the 

 actual obtaining of any data, however futile and unnecessary to the 

 one, will be a source of satisfaction to the other. Possibly a third 

 might be distinguished, who is interested only in prediction, and 

 who does not find it necessary to retard the production of hy- 

 potheses by ascertaining what the facts are. 



I believe it is rather distinctive of isolated tissues that following 

 isolation, progressive shifts occur in the water content at balance 

 (Vo). Recoveries from increments are then aiming toward a new 

 content, even as balances in control samples do. This may not be 

 universal, however, and the ideal tissue for study of equilibration 



