INTRODUCTION 1 7 



The strengths of the agglutinins are measured by the 

 addition of physiological salt solution until the mixture is 

 unable to produce a certain sharply observable agglutina- 

 tion of a given suspension of cells in a given time and at 

 a definite temperature. The dilution of this mixture is a 

 measure of its content of agglutinin as displayed toward 

 the given type of cells. 1 Madsen and Jorgensen 2 prefer 

 to measure the agglutinins according to their power of 

 clarifying a bacterial suspension. 



Even for precipitins (e.g. rennet) such a degree of pre- 

 cipitation or coagulation may be found which is rather 

 sharply defined from higher or lower degrees. By inclin- 

 ing the tubes containing the solutions to be investigated 

 we get an impression of the consistency of the contents 

 after treatment during a given time at a definite tem- 

 perature. In a similar way as for the agglutinins it is 

 possible to determine the strength of the precipitating or 

 coagulating preparations. 



The bacteriolysins have not been examined quantita- 

 tively. Their effects are studied in mixtures of suspensions 

 of bacilli which are injected intraperitoneally into animals 

 (e.g. guinea-pigs) and examined in specimens taken out 

 after a time. The method of observation makes it very 

 difficult to collect a material fit for quantitative treatment. 



1 Eisenbergand Volk: Zeitschr.f. Hygiene, 40. 155 (1902). 



2 Jorgensen and Madsen : Fcstskrift, I.e. 



