320 Quantitative Precipitin Tests 



Among the Primate bloods that of the Chimpanzee gave too high 

 a figure, owing to the precipitum being flocculent and not settling well 

 for some reason which could not be determined. The figure given by 

 the Ourang is somewhat too low, and the difference between Cyno- 

 cephalus sphinx and Ateles is not as marked as might have been 

 expected in view of the qualitative tests and the series following. The 

 possibilities of error must be taken into account in judging of these 

 figures, repeated tests should be made to obtain something like a 

 constant. Other bloods than those of Primates give small reactions or 

 no reactions at all. The high figures (10 °/o) obtained with two 

 Carnivore bloods can be explained by the fact that one gave a loose 

 precipitum, and the other was a somewhat concentrated serum. 



Tests with Antihuman Serum (2. xi. '02). Series ii. and iii. 

 Antiserum from two rabbits treated with human serum. 



Blood of 

 Man 

 906 Ourang 



364 Cynocephalus mormon 

 742 Cercopithecus petaurista 

 697 Ateles vellerosus 

 784 Cynocephalus porcarius 

 908 Macacus rhesus 



1 The succeeding amounts of precipitum are purposely omitted from the table. 



The results with the two antisera appear divergent. The first 

 antiserum ivas nearly tivice as powerful as the second, and appears to 

 cause less precipitation proportionately in the non-homologous bloods. 

 The bloods Nos. 784 and 908 were from animals which had died of 

 intussusception and dysentery respectively, these diseases, as we know, 

 tending to produce concentration of the serum during life ; and this 

 accounts fully for the very high percentage of precipitum obtained. 

 On the other hand, if we take the percentages obtained with the blood 

 of the Ourang as 100, the figures agree fairly well between the two 

 series, if we except that of Ateles, thus : 



Tiie sera of the diseased animals 

 considered separately gave with 



