AGGLUTINATION OF RED BLOOD CELLS. 317 



noted that in this experiment we used D corpuscles and not fresh 

 corpuscles. The reason that we have employed D corpuscles is 

 because they have been for a long time in contact with fluid A and 

 supposedly are very similar in tonicity to this fluid, so that they 

 have nothing more to give out into it. Under these conditions we 

 should not expect the pericorpuscular zone to be richer in salts 

 than is the fluid between the corpuscles. In tube 2, on the con- 

 trary, D corpuscles are placed in contact with saline solution that 

 does not contain the corpuscular salts, and their tonicity is there- 

 fore higher than that of the salt solution. We should expect 

 them, therefore, to diffuse their own salts and to create a pericor- 

 puscular zone that is more concentrated than the fluid between 

 the corpuscles. To sum up, in tube 1 we have a pericorpuscular 

 zone and an intercorpuscular fluid of the same concentration; in 

 tube 2 we have a pericorpuscular zone that is more concentrated 

 than between the corpuscles. The agglutination of the corpuscles 

 by calcium fluoride should therefore be more intense in tube 2 

 than in tube 1 if the salts in the pericorpuscular zone play any 

 role in the phenomenon. 



And there would be still another reason why the intensity of the 

 agglutination should differ in the tubes in our experiment if this 

 hypothesis were true. As we introduced CaFl 2 some time before 

 the corpuscles, this suspension was subjected to the flocculating 

 effect of salt solution in tube 2 and to the effect of fluid A in tube 1. 

 As fluid A contains the intracorpuscular salts it should have more 

 flocculating action than salt solution, and consequently CaFl 2 , 

 being more markedly flocculated in tube 1, should in tube 2 have 

 less effect on the corpuscles. As we have already seen, the results 

 do not justify this conception, and, what is more, CaFl 2 is not floc- 

 culated in tube 1 any more than it is in tube 2. In other words, the 

 supposed increase of salt in tube 1 from the corpuscles does not 

 give any more marked flocculation than does salt solution. 



This experiment demonstrates that the agglutination of cor- 

 puscles by CaFl 2 does not lose in intensity when the flocculating 

 effect that the pericorpuscular zone might have on the suspension 

 is reduced to the minimum. 



The objection may be raised that the diffusion of salts from the 

 corpuscles is never pushed sufficiently in such an experiment and 



