ANTIBACTERIAL AMBOCEPTORS AND COMPLEMENT 71 



the a series were obtained with a typhoid strain that had been 

 freshly cultivated from a patient, while the b series has reference 

 to a common laboratory strain. 



After 2 to 3 After 5 to G After 24 to 25 



Original count. hours. hours. hours. 



Series a ... 10221 to 12256 2074 to 4275 3217 to 4664 8344 to 39125 

 Series 6 ... 2016 to 6586 to to to 



Specificity of Normal Antibacterial Amboceptors and Complement. 

 Practically important is the fact that the normal thermostabile 

 antibacterial amboceptors are specific, as can be shown by treating 

 an inactivated serum with cholera vibrios, for example, when it will be 

 noted, after removal of the organisms by centrifugation, that the 

 fluid, upon the addition of suitable complement, has lost the power 

 of causing the destruction of newly added cholera organisms, while 

 it is still destructive for typhoid organisms. In other words the anti- 

 cholera amboceptors have been extracted, while the antityphoid 

 amboceptors have not been affected by the first extraction. 



Detailed analytical studies of the different kinds of amboceptors 

 contained in normal human serum are apparently lacking, but it 

 appears from what has been done that whereas anticholera, anti- 

 typhoid, anticolon, and antidysentery amboceptors are usually to be 

 found, normal blood possesses no bactericidal power over the various 

 staphylococci, the pneumococcus, micrococcus melitensis, bacterium 

 pestis, bacillus xerosis, and the diphtheria bacillus, nor do such 

 substances appear in the human being as the result of infection. 



Providing that suitable complement is present, bacteriolysis 

 will, of course, occur whenever blood serum containing a given 

 amboceptor is brought in contact with the corresponding bac- 

 teria. As a general rule the complement of the same serum as that 

 containing the amboceptor, or at any rate that from an animal 

 of the same species, will be found to be effective, but there are a 

 number of curious exceptions. The serum of the human being, of the 

 ox, and of the dog thus contains anti-anthrax amboceptors, which are 

 not activated by the corresponding complement. Such sera per se have 

 no bactericidal action whatever for the organism in question, while 

 the addition of a little rabbit serum renders them active. The recog- 

 nition of the fact that the serum of an animal of a different species 

 may contain complement that will activate a given amboceptor is of 

 great practical interest, as it is often technically more convenient 



