70 IMMUNE SERA 



meningococcus sera and also in diagnosing syphilitic 

 antigens and antibodies. 



Neisser and Sachs 1 have recently described a pro- 

 cedure for the forensic diagnosis of blood stains. The 

 principle of this is the same as in the preceding although 

 in so far as a specific precipitin serum is made use of, 

 the procedure is really modelled after the " Gengou- 

 Moreschi " phenomenon. 



If human blood serum is mixed with a specific 

 human precipitin serum derived from rabbits, it will 

 be found that the mixture binds complement. Has- 

 molysin subsequently added is unable to dissolve its 

 specific red blood cells, owing to this locking up of 

 the complement. Only the serum of monkeys has a 

 similar effect. The amount required is extremely 

 minute, yiroVoo "to T ooVo cc - human blood or monkey 

 blood sufficing. Extracts of human blood stains will also 

 produce the desired effect. The authors believe that 

 the immunization with human blood serum gives rise 

 not only to precipitins but also to amboceptors which 

 then are able to unite with their corresponding unformed 

 albuminous bodies and so bind complement. Others 

 are of the opinion that the complement is bound by 

 the precipitin-precipitum combination. 



The test is extremely delicate and has been found 

 trustworthy by a number of investigators. In view 

 of the importance of such tests in medico-legal cases, 

 Neisser and Sachs suggest that it should always be 

 used in addition to the well known Wassermann- 

 Uhlenhuth precipitin test. 



Normal Serum, its Haemolytic and Bacteriolytic 

 Action. Inquiring now into the essential differ- 



1 Neisser and Sachs, Berliner klin Wochenschrift, 1905. 



