Antiprecipitins: Normal and Artificial 149 



ANTIPRECIPITINS. 



Normal Antiprecipitins. I have noted elsewhere (p. 145) that Halban 

 and Landsteiner (25, in. 1902, p. 475) observed a difference between 

 maternal and foetal serum with regard to their reactions to precipitins. 

 This difference appears to me to depend upon the possible existence of 

 normal antiprecipitins, analogous to the normal antihaemolysins observed 

 by Besredka (1901) (see p. 22). Halban and Landsteiner found that 

 the addition of large quantities of human serum to its antiserum 

 prevented precipitation (but this might be explained in the light of 

 what I have stated elsewhere, viz., that a precipitum is soluble in an 

 excess of its homologous blood), whereas, additions of large quantities of 

 ox or horse serum were less effective, and dog, fowl, and fresh rabbit 

 serum did not prevent precipitation. Similarly, the authors I have cited 

 found that anti-ox serum acted least upon the addition of much ox 

 serum, more markedly upon adding the serum of the horse, most when 

 the sera of the dog, man, rabbit, and fowl were added. That is to say, 

 the latter did not impede the reaction. It is possible, it seems to me, 

 that this appearance may be due to normal antiprecipitin, or precipito- 

 lysin if I may so term it, which is present only in small quantity in 

 normal serum, and therefore only exerts an obvious effect when large 

 amounts of a serum are added to an homologous antiserum. (See 

 Observation in. p. 89.) 



Artificial Antiprecipitins have been produced by Kraus and 

 Eiscnberg ( Wiener klin. Wochenschr., 1901, p. 1191 ; see also 27, n. 1902, 

 p. 212 213) through treating goats with goat-lactoserum obtained from 

 rabbits which had been treated with goat's milk. They found that 

 antilactoserum prevented the precipitation of milk by lactoserum. In 

 addition, the antilactoserum contained antihaemolysin, which was 

 natural, for the goat lactoserum (obtained from rabbits) was haemolytic 

 for goat's red blood corpuscles. 



Schlitze (2, xil. 1901) has also succeeded in obtaining antilactosera, 

 which, as stated above, are analogous to the antihaemolysins (see p. 21). 

 Schiitze's antiprecipitin retarded or prevented the precipitation of milk 

 by its homologous antiserum. 



It remains to be determined if injections with precipitoids, which 

 have been compared to toxoids, will lead to the formation of antipreci- 

 pitins, as toxoids do of antitoxins, as discovered by Ehrlich (1900 

 Croonian Lect.). I propose to see if this is possible. 



