502 THE BIOLOGICAL BASIS OF INDIVIDUALITY 



More recently, Landsteiner and Miller were able to differentiate between 

 the blood of man, of chimpanzee and orang-utan by means of immune hemag- 

 glutinins, which they produced in rabbits, against these various types of 

 erythrocytes, but it was necessary first to remove, by specific absorption, the 

 non-specific agglutinins which these species had in common. These investi- 

 gators found that the differences between the blood of man and chimpanzee 

 or orang-utan are less marked than those between these species and the 

 lower monkeys. As mentioned above, Landsteiner and Levine furthermore 

 succeeded in obtaining hemagglutinins which agglutinated only human but 

 not chimpanzee erythrocytes, by injecting a chimpanzee with human erythro- 

 cytes, in this manner applying Uhlenhuth's method to the hemagglutinin test. 

 In still another and more simple way they were able to differentiate between 

 human and chimpanzee blood by the use of the preformed heteroagglutinins 

 which occur in ox serum. After absorption with chimpanzee erythrocytes, ox 

 serum still agglutinated human corpuscles very strongly and, conversely, after 

 absorption with human corpuscles it was still active towards chimpanzee 

 blood. 



Certain additional methods were employed for the purpose of grading the 

 relationship of antigens derived from different species. Thus alcohol extracts 

 of various types of blood corpuscles in combination with a foreign serum, 

 the protein of which served as carrier, could be used as antigens for the 

 production of hemolysins. When these alcohol soluble, partial antigens were 

 acted upon by the specific, heat-inactivated hemolytic immune sera, a floccula- 

 tion and also a fixation of complement occurred, which were specific. Specific 

 complement fixation has been employed for the testing of graded relationships 

 of antigens by various investigators. Many years ago, Bruck believed that it 

 was possible to demonstrate, through complement fixation, differences even 

 between the blood of different human races, such as European, Malay, Arab 

 and Chinese. However, this observation could not be confirmed by Marshall 

 and Teague, nor by Fitzgerald ; nor were Landsteiner and Miller able by 

 serological methods to demonstrate differences between the blood cells of the 

 white race and the Negro. 



A further test for the specificity of antigens, especially of haptens which 

 are non-protein components of antigens, was introduced by Landsteiner. Such 

 haptens, which when injected alone into an animal belonging to a foreign 

 species do not call forth the production of antibodies, do so if they are 

 combined with a foreign protein acting as the carrier of the specific substance. 

 But even without the aid of a carrier they may be able to inhibit in a specific 

 manner the reaction between the antigen and the specific immune serum, 

 irrespective of whether this reaction consists in precipitation, hemolysis, or 

 hemagglutination. 



Also, anaphylactic reactions have been used, especially by Wells and Os- 

 borne, for the testing of the organismal specificity of certain substances. These 

 investigators worked with alcohol soluble proteins from various seeds, such 

 as gliadin from wheat and rye, hordein from barley, zein from maize. First 

 they showed that the occurrence of anaphylactic shock in sensitized guinea 



