394 INFECTION AND RESISTANCE 



with an explosive liberation of the toxic fraction and consequent 

 symptoms. 27 



Nicolle believes that the injection of a protein into an animal induces 

 the production in the subject of antibodies. These are preeminently two 

 albuminolysins, which cause its cleavage, and albuminocoagulins or precipi- 

 tins, which coagulate and prevent the action of the lysin. At the time at 

 which an animal is hypersusceptible or anaphylactic there has been a pro- 

 duction of albuminolysins which cause cleavage of the protein, with the 

 rapid liberation of toxic substances; but the albuminocoagulins or precipi- 

 tins have not yet adequately developed. In a refractory animal the neu- 

 tralizing action of the albuminoprecipitins prevents the harm which the 

 lytic action might otherwise accomplish. The relative amounts of these 

 two antibodies present in the circulation of the animal at any particular time 

 determine whether the animal is anaphylactic or refractory or immune. This 

 theory assumes arbitrarily the protective nature of precipitation, an idea 

 which has no foundation in experiment and, in fact, is rendered extremely 

 unlikely by more recent developments of our knowledge of the precipitating 

 antibodies. 



Given, then, a reasonable hypothesis in which anaphylaxis is 

 associated with the cleavage of protein by lysis, given, in other words, 

 an antigen-antibody conception, it is but natural that experimenters 

 should ask themselves: What is the relation of the alexin to this 

 cleavage ? For in all known lytic reactions, of course, the union of 

 antigen and antibody leads to the absorption of alexin, by means of 

 which, then, the lysis takes place. This problem suggested itself to 

 a number of the earlier investigators who attempted to approach it 

 by determining whether or not the sera of sensitive animals, added 

 to antigen, would fix alexin. Gay and Southard, Sleeswijk, 29 and 

 others obtained negative results, while Nicolle and Abt, 30 and Doerr 

 and Russ 31 obtained positive results. As far as this particular 

 method is concerned, therefore, no conclusions can be drawn. Slees- 

 wijk, however, has approached the question in another way and ex- 

 amined whether or not there is a diminution of alexin in the blood of 

 an animal immediately after anaphylactic shock. He found that 

 this was indeed a regular occurrence, and his results have been con- 

 firmed by Friedberger and Hartoch 32 and a number of others. 



It was shown by these workers that, both in active and passive 

 anaphylaxis in rabbits and dogs, as well as in guinea pigs, there is a 

 definite and considerable diminution of complement immediately 

 after anaphylactic shock. 



27 For the sake of completeness it is well also to mention Nicolle's 28 

 theory, which, though attractive, is not borne out by recent knowledge con- 

 cerning the nature of precipitins. 



28 Nicolle. Ann. de Vlnst. Past., Vol. 22, 1908. 



29 Sleeswijk. Zeitschr. f. Immunitatsforschung, Vol. 2, 1909. 



30 Nicolle and Abt. Ann. de I'Inst. Past., Vol. 22, 1908. 



31 Doerr and Russ. Zeitschr. f. Immunitatsforschung, Vol. 3, 1909. 



32 Friedberger and Hartoch. Zeitschr. f. Immunitatsforschung, Vol. 3, 

 1909. 



