SECTION IV. 



ON THE SPECIFICITY OF PRECIPITINS. 



THAT no special attention had been paid to the reactions which may 

 take place in non-homologous bloods upon the addition of powerful 

 antisera, prior to my publications, would seem clear from a comment 

 upon one of my papers by Rostoski (1902, b, p. 18), who writes: "Die 

 Angaben von Nuttall, dass das Serum eines init Menschenblut be- 

 handelten Kaninchens auch eine schwache Triibung in Blutlosungen 

 des Pferdes, des Ochsen und des Schafes hervorrufe, wiederspricht alien 

 andern Beobachtungen direkt" ! We shall see, however, that my 

 observations have since been confirmed by several investigators. 



Ehrlich (22, in. 1900) appears to have been the first to attribute 

 " a rigidly specific " character to the precipitins, basing his statement 

 upon the investigations of Bordet and Myers, and speaking of the 

 precipitins as " specific coagulines which act only in a specific manner, 

 i.e. precipitate only the albuminous body injected." It was natural 

 that he was led to this conclusion in view of the results of the investi- 

 gations he cited, which, however, were based on but a very limited 

 number of tests upon non-homologous material. Michaelis (9, x. 1902, 

 p. 733) refers to Wassermann (1900, p. 501), saying he " fiihrte zuerst 

 grundlegend aus, dass die Reaktionen streng specifisch fur die injicirte 

 Eiweissart sind," although on the next page (p. 734) he contradicts this 

 by saying that the specificity of the reaction is not " absolutely strict." 

 Wassermann and Schiitze (2, VII. 1900), it will be remembered, stated 

 that ox-lactoserum, for instance, did not act on goat milk and vice versa, 

 whereas other observers since, notably Moro (31, X. 1901, see further 

 under Lactosera, p. 157), have found the contrary to be the case, doubt- 

 less because they used stronger antisera, or made their observations at 

 a later period, after milk and antiserum had been brought in contact. 

 Uhlenhuth (7, n. 1901) was apparently the first to consider that it 



