xm, b, 3 Monserrat: Study on Natural Hemolysins 161 



It is evident from the results of the tests given in Table III 

 that monkeys' serum behaves in the same way as human serum 

 does with regard to natural amboceptor toward the various red 

 corpuscles used in the test. Furthermore human red cells and 

 those of a monkey behave in practically the same way when 

 exposed to the action of inactivated sera of various animals and 

 guinea pigs' complement. 



One striking thing, which may be of interest, is the finding 

 that rabbits' serum contains no hemolytic amboceptor for human 

 corpuscles, while it has a large amount of natural hemolytic 

 amboceptor for monkeys' red corpuscles. Monkeys' red cells 

 behave in that respect in a similar way as those of the sheep, 

 the horse, and the goat. This finding probably explains the fact 

 that artificial antimonkey amboceptor of as high titer as that 

 of the sheep, the goat, and the horse can be produced. 



This question is being studied in further experiments now 

 under way. 



The object of these experiments is to test more than one 

 rabbit's serum and to study the influence of immunization on the 

 amount of natural hemolytic amboceptor. 



. CONCLUSIONS 



1. Inactivated human sera contain no natural amboceptor for 

 monkeys' red corpuscles, but a great percentage of human sera 

 contains a large amount of hemolytic amboceptor for sheep's 

 and goats' corpuscles. 



2. Inactivated monkeys' serum contains no natural amboceptor 

 for human red corpuscles, but contains a large amount of natural 

 hemolytic amboceptor for sheep's and goats' corpuscles. 



3. Natural hemolytic amboceptor of human and monkeys' sera 

 are almost identical, not having the same relation in this respect 

 with the sera of the sheep, the horse, the cow, the goat, the 

 rabbit, and guinea pig. 



4. The serum of the rabbit (one animal) shows hemolysins for 

 the corpuscles of the sheep, the horse, the monkey, and the goat. 



