SUSCEPTIBILITY AND IMMUNITY. 



be the active agent in blood serum by which certain pathogenic bac- 

 teria are destroyed, as shown by the experiments of Nuttall, Buchner, 

 and others. Hankin had previously isolated an albuminoid sub- 

 stance from the spleen and blood of the rat, to which he ascribed the 

 immunity of this animal from anthrax. This substance, according 

 to the author named, is a globulin; it is insoluble in alcohol and in 

 distilled water, and does not dialyze. 



Tizzoni and Cattani ascribe the protection of animals which have 

 acquired an immunity against tetanus to the presence of an albumi- 

 nous substance which they call the tetanus-antitoxin. This they 

 have isolated from the blood of immune animals. They arrive at 

 the conclusion that it is a globulin, or a substance which is carried 

 down with the globulin precipitate, and that it is different from the 

 globulin, above referred to, obtained by Hankin from animals im- 

 mune against anthrax. 



G. and F. Klemperer, in 1891, published an important memoir in 

 which they gave an account of their researches relating to the ques- 

 tion of immunity, etc., in animals subject to the form of septicaemia 

 produced by the Micrococcus pneumonia crouposaB. They were able 

 to produce immunity in susceptible animals by introducing into their 

 bodies filtered cultures of this micrococcus, and proved by experiment 

 that this immunity had a duration of at least six months. They 

 arrived at the conclusion that the immunity induced by injecting fil- 

 tered cultures is not directly due to the toxic substances present in 

 these cultures, but that they cause the production in the tissues of an 

 antitoxin which has the power of neutralizing their pathogenic 

 action. The toxic substance present in cultures of the "diplococcus 

 of pneumonia" they call " pneumotoxin" ; the substance produced in 

 the body of an artificially immune animal, by which this pneumo- 

 toxin is destroyed if subsequently introduced, they call " anti -pneumo- 

 toxin." 



Emmerich, in a communication made at the meeting of the In- 

 ternational Congress for Hygiene and Demography, in London, re- 

 ported results which correspond with those of G. and F. Klemperer 

 so far as the production of immunity is concerned, and also gave an 

 account of experiments made by Donissen in which the injection of 

 twenty to twenty-five cubic centimetres of blood or expressed tissue 

 juices, filtered through porcelain, from an immune rabbit into an 

 unprotected rabbit, subsequently to infection with a bouillon culture 

 of "diplococcus pneumonia," prevented the development of fatal 

 septicaemia. Even when the injection was made twelve to fifteen 

 hours after infection, by inhalation, the animal recovered. 



Emmerich and Mastraum had previously reported similar results 

 in experiments made upon mice with the Bacillus erysipelatos suis 



