6o 



Scientific Proceedings (27). 



In normal rabbits and guinea-pigs the percentage of hemolysis 

 in a salt solution of given concentration is found to be in surpris- 

 ing correspondence between individuals of the same species. The 

 mean isotonic solution in twenty two determinations of rabbit 

 blood, comprising seventeen individuals, was found to be between 

 0.65 per cent, and 0.7 per cent, sodium chloride. In nine guinea- 

 pigs the isotonic mean was found to be o. 1 per cent, salt solution 

 lower than that of rabbits' blood (0.55 per cent, to 0.6 per cent.). 

 The comparison of the freezing point of the whole defibrinated 

 blood and of the blood serum of these two species, in several indi- 

 viduals, showed a corresponding difference in the freezing point of 

 from o.04°-o.o6° C. 



Rabbits were immunized with B. typliostis or B. ozence or the 

 blood of guinea-pigs respectively ; guinea-pigs were immunized 

 with rabbit blood. In from nine to fourteen days after the last of 

 several injections these animals were bled, the resistance of their 

 corpuscles tested, and in many instances the freezing points of their 

 defibrinated blood or of their sera determined. As regards the 

 resistance of their corpuscles to salt solutions it was found that in 

 every case it was increased in the immunized animal in an amount 

 usually corresponding to a o. 1 per cent. NaCl solution. This rela- 

 tive difference in the resistance to hemolysis between the blood of 

 normal and of immunized animals was controlled in as many ways 

 as suggested themselves ; animals were tested before and after 

 immunization ; normal animals were tested several different times ; 

 and in each instance normal and immunized animals were tested 

 at the same time. In every instance the relative difference between 

 normal and immunized animals would seem as definite as is indi- 

 cated by the mean results. 



In order to assert that this increased resistance of corpuscles 

 in the blood of immunized animals to hypotonic solutions indicates 

 a lower tonicity of the blood as a whole, it would be necessary to 

 determine a corresponding difference in the molecular concentra- 

 tion of the blood or sera by freezing-point determinations. A 

 considerable number of such determinations have been made but 

 with results not wholly in accord with the corpuscle resistance 

 method. In perhaps the majority of instances an actually higher 

 freezing point (lower tonicity) is obtained for the immunized animals. 



