Ill 



ments. Usually the corpuscles sink to the bottom, so 

 that a moderate shaking was sufficient to obtain uni- 

 form results. Perhaps the above irregularity may be 

 accounted for, that also in the case of not agglutinating 

 blood a smaller number of corpuscles than usual by 

 some accident may have got into some of the test tubes. 

 Oilier reasons may be added for such errors of experi- 

 ment as, for instance, the difficulty of measuring small 

 quantities with sufficient exactitude. We therefore avoided 

 as far as possible measuring smaller quantities than 

 0,2 cc. Were smaller doses necessary, a dilution 1 : 5 or 

 1 : 10 was used. 



Through using many test tubes in one series, it was 

 easy to discover such accidental errors and eliminate 

 their effect. Yet it happened sometimes that a whole 

 series deviated from the normal series. For such rea- 

 sons it is necessary to have a great many control ex- 

 periments to avoid mistakes. It is therefore only a small 

 part of our experiments, which are given here. 



The experiments have, as a rule, had as their object, 

 to determine the hannolytic power of various mixtures 

 of toxin. From each mixture of toxin, a series was prepa- 

 red according to the above method. The different series 

 were treated as uniformly as possible, and after the 

 corpuscles had subsided (during a period of 20 hours 

 in the ice safe) the dissolved amount of blood was esti- 

 mated through comparing the colours by means of a 

 scale. The colour scale was easily prepared in the fol- 

 lowing manner: 2,5 cc. red blood corpuscles were added 

 to 97,5 cc. pure water, whereupon complete haemolysis 

 occurred and a coloured fluid was obtained. The co- 

 lour strength of this was put at 100. Through diluting 

 it in proportions 1 : 2, 1 : 4, 1 : 5 etc. the degrees of co- 

 lour 50, 25, 20 etc. were obtained, corresponding to a 



