146 On the Specificity of Precipitins 



p. 475) report that anti-human serum gave reactions with higher dilutions 

 of adult serum than of foetal serum. On the other hand, foetal serum 

 gave more clouding in strong dilutions than did adult blood. Evidently 

 an excess of normal serum checks precipitation, and this seems to me to 

 be due possibly to normal antiprecipitins (see p. 149). It would appear 

 that normal maternal serum contains more precipitable substance, and 

 more antiprecipitin, than foetal serum. These differences however by 

 no means indicate that maternal serum contains more globulins, for 

 the precipitin reaction as we have seen (p. 98) does not constitute a 

 quantitative test for albumins. 



Uhlenhuth (5, vii. 1902), using antiserum for fowl's egg-white (from 

 rabbit) found it to precipitate the serum of the hen much more than 

 that of the cock, the sera of sexually mature animals being used in both 

 cases for comparison. The reactions of the sera were so markedly 

 different, that he found it easy to distinguish the one from the other. 



He therefore refers to a sexual reaction (Geschlechtreaktion), and 

 proposes to see if it is possible to distinguish between the mammalian 

 sexes in a similar manner. 



Oil the Character of the Precipitins in different Species of Animals 

 treated with the same Blood. 



It has been accepted for the bacterial antitoxins obtained from 

 different animals that they are similarly constituted, whatever their 

 source. This would appear to be different for the precipitins, judging 

 from results obtained by Ascoli (26, Viii. 1902), who, to begin with, 

 remarks that because two individuals, even of one species, yield sera 

 Avhich react equally to their homologous precipitin, we have no right 

 to conclude that the sera of the two individuals are chemically identi- 

 cal, the reaction being perhaps insufficiently hne to demonstrate differ- 

 ences which actually exist. That he is right in saying this receives 

 confirmation from what has been observed with regard to the isopreci- 



tained more salts. Doleris and Quinquand (1893) made similar observations. Halban 

 (1900) found foetal blood corpuscles to be agglutinated by maternal serum, and vice versa, 

 whilst the sera showed differences in liaemolytic and bacteriolytic power. Schumacher also 

 found maternal serum to agglutinate B. typhosus better than foetal serum. According to 

 Halban and Landsteiner [luc. cit.) maternal serum is more liaemolytic tlian foetal, it ag- 

 glutinates red blood corpuscles more powerfully, it is more powerfully bacteriolytic (tested 

 on the cholera vibrio), it is more anti-fermentative (antitryptic), more antitoxic (as against 

 the haemagglutinins of abrin and riciu), and finally it yields moie precipitum with preci- 

 pitating antisera, 



