12 EXPERIMENTS DEALING WITH 



so, as the effect of injections of concentrated solutions of 

 crystalloids and solutions of bile salts or haemoglobin show. 



They further point out that the absence of lymph flow from 

 a resting limb and its presence in an active one can be 

 explained, without invoking the impermeability of capillaries to 

 proteid, by admitting exactly the opposite, namely, that the 

 wall is readily permeable to proteids. For in the resting limb 

 proteid, like 2 and other substances in solution, would be con- 

 veyed to the tissue cells by diffusion without any accompanying 

 transference of the solvent. But in the active limb, when this 

 mode of providing nutriment would not suffice, there would be 

 added pressure filtration, carrying proteid and the other dissolved 

 substances along with the solvent and at the same rate. But 

 this fails to explain why liver lymph is so wholly different in 

 its proteid content from that obtained from a limb even during 

 its greatest activity ; especially when we consider how much 

 lower the capillary pressure in the liver probably is. Further, 

 it offers no obvious explanation of the action of curare, which 

 reduces capillary pressure and yet raises the proteid content of 

 the lymph from a limb up to that from the liver, a rise which 

 no activity of the limb can bring about. 



They attempt to show that even granting Starling's premises, 

 the osmotic pressure of proteids could not effect absorption. 

 They point out the obvious fact that the total osmotic pressure 

 of plasma against an otherwise isotonic salt solution is not avail- 

 able for absorption, but has to be reduced because of the presence 

 of proteid in tissue fluid, and because the capillary wall is partially 

 permeable to proteid. It is impossible to estimate the magnitude 

 of this correction ; but they estimate that a force of only 6 mm. Hg 

 is available for absorption. It is clear that absorption could 

 only take place when the force tending to cause it is greater than 

 the force tending to produce filtration, i.e. when the available 

 osmotic pressure of the plasma proteid is greater, not than the 

 capillary blood pressure as they state, but than the difference 

 between the hydrostatic pressures of the intravascular and 

 extravascular fluids, which is a very different thing. Considering 

 our complete ignorance of the actual numerical values of the 

 three factors concerned, it is impossible to say more than that 

 Starling's view is not known to be impossible. 



Waymouth Reid has brought forward evidence to show that 



