138 On the Specificity of Precijiitins 



chimpanzee, which he states " gave a slight but distinct tnrbidity after 

 a few hours with horse blood." In a paper which I published almost 

 simultaneously (20, I. 1902) I stated that when testing bloods it is 

 necessary " to j^ut a time limit upon them. This may appear to be a 

 rather arbitrary proceeding. My time limit has usually been 5 minutes 

 at average temperatures in the laboratory. A powerful antiserum will 

 certainly have acted within that time upon its homologous blood- 

 dilution ; with powerful fresh antisera the reaction takes place almost 

 instantaneously. On the other hand, if we allow mixtures of avtisera 

 and bloods to stand, a reaction takes 'place luith non-honiologons bloods. 

 The results I have hitherto obtained tend however to prove that anti- 

 mammalian sera only produce these later reactions in mammalian bloods, 

 anti-avian sera similarly in avian sera alone." 



Furthermore Linossier and Lemoine (8, III. 1902) state that in view 

 of the unanimity amongst authors regarding the strictly specific 

 character of these reactions, they were surprised to find antisera not so 

 specific as had been supposed. They found that a precipitin may act on 

 a number of different bloods, although the degree of reaction varies. 

 As a rule, they state that the precipitum obtained is least voluminous in 

 bloods of distantly related animals to the one whose blood has been used 

 for the jDroduction of the antiserum. Their method of testing with 

 concentrated sera is different from mine and is subject to criticism, as 

 will be seen by reference to pages 74 and 89. And this will account 

 for their obtaining a reaction even with fowl serum, as stated 

 below. They added anti-human, anti-horse, and anti-ox serum in the 

 proportion of 10 volumes to 1 of the different sera tested, viz. those of 

 man, dog, ox, sheep, horse, jjig, guinea-pig, fowl, and obtained a 

 precipitum in all of these bloods. With the exception of the fowl's 

 blood in which the reaction was minimal, and the guinea-pig's in 

 which it was feeble, all gave well-marked reactions. None of the 

 antisera acted on rabbit serum. They noted what appeared to be a 

 faint clouding in the serum of the eel. Judging from these results, 

 which are anomalous in some respects, it would appear desirable to 

 make a series of tests with a large number of sera under the same 

 conditions. I have not as yet had an opportunity of doing so. Halban 

 and Landsteiner (25, iii. 1902, p. 475) state in a footnote, that 

 their haematosera (presumably anti-human) also acted to a very slight 

 degree on substances (serum and milk probably meant) of other not 

 closely related animals. Anti-human scrum produced " spurweise 

 Pracipitation," that is, traces of precipitation, with horse-, but not with 



