( 35 ) 



ratelj the quantity of precipitate which is formed by the precipitin 

 reaction. This method also permitted tr» investigate quite generally 

 the conditions ^vhich nilo the formation of precipitate from the two 

 components. 



Immediately two fticts had pushed themselves forward by a preli- 

 minary study which were also stated in another way by Eisenberg ') 

 and AscoLi ^). 



1. That when to a fixed quantity of calfserum ') (precipitin ^= 

 antitoxin) increasing (quantities of diluted horseserum (pi'ecipitinogen 

 substance = toxin) were added, the quantity of precipitate increased, in 

 order to decrease by further admixture of diluted horse serum. 



2. that whatever may have been the proportion in which the two 

 components were added to each other, the clear liquid delivered 

 from precipitate always give a new precipitate with each of the 

 components separately. This leads to the conclusion that here is 

 question of an equilibrium reaction in the sense as it has been 

 stated and explained for the first time by Arrhenius and ^Iadsen ''). 



This conclusion has become also the starting point of the now 

 following researches of iv/iich the purpose mas to investigate by 

 quantitative iixuj the principal conditions by which precipitin reaction 

 is ruled. 



Methods of investigation. 



To a fixed quantity of calfserum') (precipitin =i antitoxin) increas- 

 ing quantities of diluted horse-serum (precipithiogen subslance = 



1) Eisenberg. Beitrage zur Kenntniss der specifischen Pracipitalionsvorgange 

 Bulletin de I'Acad. d. Sciences de Cracovie. Glass, d. Sciences Mathem. et nat. 

 p. 289. 



-) AscoLi. Zur Kenntnis dcr l^racipitinewirkung. Miinchener Med. Wochenschr. 

 XLIX Jahrg. S. 398. 



3) They used sera of other animals. 



*) Arrhenius und Madsen. Physical chemistry to toxins and antitoxins. Fest- 

 skrift ved indvielsen of Statens Serum Institul. Kjobenhavn 1902; Zeitschr. f. 

 physik. Chemie 44, 1903, S. 7. 



In many treatises the authors have continued these investigations ; compare e.g. 

 still : 



Arrhenius. Die Anwendung der physikalischen Chemie auf die Serumtherapie. 

 Vortrag gehalten im Kaiserl. Gesundheitsamt zu Berlin am !22 Sept. 1903. Arbeiten 

 aus dem Kaiserl. Gesundheitsamt 20, 1903. 



Arrhenius. Die Anwend. der physik. Chemie auf die Scrumtherapeutischen Fragen. 

 Festschrift f. Boltzmann 1904. Leipzig, J. A. Barth. 



5) To make it easy for the reader, we speak here only of calfserum and horse- 

 serum. Compare the third note on this page. 



3* 



