ARNOLD H. EGGERTH AND MARGARET BELLOWS 



677 



isoelectric point of edestin, though in a later paper Michaelis and 

 Mendelssohn (1914) give it a value of pH 5.6. 



In the experiment shown in Table VI, a 0.25 per cent suspension of 

 edestin in distilled water was dissolved by the addition of minimal 

 alkali; the solution was immediately distributed in the buffer mixtures 

 and incubated at 40°C. for 30 minutes. The 1 : 1 ,600 dilution of edestin 

 gave a small precipitate in the pH 5.3 tube, and a heavier flocculent 

 precipitate in the tubes alkaline to this. Bacterium coli suspension was 

 then added without stirring up the precipitate that had formed. 



TABLE VI. 



Bacterium coli Suspension with Edestin. 

 1. cc. buffer mixture + 0.5 cc. edestin solution + 0.5 cc. coli suspension. 



Temperature = 40°C. X = agglutination within 30 minutes. + = aggluti- 

 nation within 6 hours. 



Flocculation with Hemoglobin. 



Crystallized oxyhemoglobin was prepared from the blood of the 

 horse, the dog, and the guinea pig, some by the method of Hoppe- 

 Seyler (1903), and some by the method of Dudley and Evans (1921). 

 No marked differences in behavior were observed between these 

 crystallized oxyhemoglobins and other solutions prepared by laking 

 washed erythrocytes and centrifugating out the stroma. In the 

 results obtained, there were some differences between the hemo- 

 globins of different species of animals, and between the oxy- and 

 methemoglobins of the same species. 



It will be observed that in the most concentrated hemoglobin 

 that we used (Table VII) the zone of flocculation extended only 

 as far toward the alkaline side as pll 6.2 (in some experiments, 



