[42] Uhlenhuth, P., and Steffenhagen, K., Kolle-Wassermann, _Handb. d. pathol. Mikroorg._, 2nd Ed., 1913, iii., 257.
To Nuttall[43] belongs the credit of having worked out a quantitative method for measuring the amount of precipitate formed, and in this way he made it possible to draw more valid conclusions concerning the degree of specificity of the precipitin reaction. He found by this method that when the immune serum is mixed with the serum or the protein solution used for the immunization a maximum precipitate is formed, but if it is mixed with the serum of related forms a quantitatively smaller precipitate is produced. In this way the degree of blood relationship could be ascertained. He thus was able to show that when the blood of one species, _e. g._, the human, was injected into the blood of a rabbit, after some time the serum of the rabbit was able to cause a precipitate not only with the serum of man, or chimpanzee, but also of some lower monkeys; with this difference, however, that the precipitate was much heavier when the immune serum was added to the serum of man. The method thus shows the existence of not an absolute but of a strong quantitative specificity of blood serum. This statement may be illustrated by the following table from Nuttall. The antiserum used for the precipitin reaction was obtained by treating a rabbit with human blood serum. The forty-five bloods tested had been preserved for various lengths of time in the refrigerator with the addition of a small amount of chloroform.
[43] Nuttall, George H. F., _Blood Immunity and Blood Relationship_, Cambridge Univ. Press, 1904.
QUANTITATIVE TESTS WITH ANTI-PRIMATE SERA
---------------------------+--------------+------------------------- Blood of | _Precipitum_ | _Percentage_ | _Amount_ | ---------------------------+--------------+------------------------- _Primates_ | | Man | .031 | 100 Chimpanzee | .04 | 130 (loose precipitum) Gorilla | .021 | 64 Ourang | .013 | 42 Cynocephalus mormon | .013 | 42 Cynocephalus sphinx | .009 | 29 Ateles geoffroyi | .009 | 29 | | _Insectivora_ | | Centetes ecaudatus | .0 | 0 | | _Carnivora_ | | Canis aureus | .003 | 10 (loose precipitum) Canis familiaris | .001 | 3 Lutra vulgaris | .003 | 10 (concentrated serum) Ursus tibetanus | .0025 | 8 Genetta tigrina | .001 | 3 Felis domesticus | .001 | 3 Felis caracal | .0008 | 3 Felis tigris | .0005 | 2 | | _Ungulata_ | | Ox | .003 | 10 Sheep | .003 | 10 Cobus unctuosus | .002 | 7 Cervus porcinus | .002 | 7 Rangifer tarandus | .002 | 7 Capra megaceros | .0005 | 2 Equus caballus | .0005 | 2 Sus scrofa | .0 | 0 | | _Rodentia_ | | Dasyprocta cristata | .002 | 7 (concentrated | | serum clots) Guinea-pig | .0 | 0 Rabbit | .0 | 0 | | _Marsupialia_ | | Petrogale xanthopus } | | Petrogale penicillata } | | Onychogale frenata } | | Onychogale unguifera } | .0 | 0 Onychogale unguifera } | | Macropus bennetti } | | Thylacinus cynocephalus} | | ---------------------------+--------------+-------------------------