BACTERIOLYSIS AND ALLIED PHENOMENA 195 



characteristic necrosis of the stomach, so that its immune body 

 cannot be reactivated by guinea-pig alexin; but the latter body 

 can reactivate haemolysin prepared by immunizing rabbits with 

 guinea-pig's corpuscles. If the serum is placed in contact with 

 an emulsion of guinea-pig's mucous membrane, it becomes 

 innocuous, both immune bodies being absorbed ; but when 

 saturated with red corpuscles, it loses its haemolytic power, and 

 retains its necrotizing properties. 



Rabbits injected with emulsions of rabbit's mucous membrane 

 develop a gastrotoxin which acts on guinea-pigs, but not on the 

 rabbit itself. Similarly for guinea-pigs treated with emulsions of 

 mucous membrane from the same species : their serum becomes 

 gastrotoxic for the rabbit, not for the guinea-pig. 



To account for these remarkable facts it is suggested that the 

 gastrotoxin has two cytophile groups one which combines with 

 the gastric cells of the animal which produces it, and one which 

 combines with those of the other species. Thus the gastrotoxin 

 of the rabbit has a cytophile group, a, which has an affinity for 

 rabbit's gastric cells, and a second, 6, which unites with those of 

 the guinea-pig. During the process of immunization the animal 

 produces an anti-immune body, which combines with the cytophile 

 group a, but not with b. This is readily explicable on the side- 

 chain theory. It follows, therefore, that the gastrotoxin is never 

 efficacious against the species which produces it, being always 

 neutralized as regards these cells by a partial anti-antibody. 



Anti-intestinal serum has been prepared. It is extremely toxic, 

 causing gangrene of the mucous membrane and death. Less 

 powerful sera cause non-fatal diarrhoea. 



Syncytiolysin, or placentolysin, has been obtained by injections of 

 emulsions of placental tissue. According to Liepman the serum 

 thus obtained will give a precipitate with a solution of placental 

 tissue, with blood from the umbilical vein, or even with that of 

 a gravid woman, but not that of a non-gravid woman or a man ; 

 hence he proposed a serum test for pregnancy. But his results, 

 which seemed highly improbable, have been disproved by 

 Weichardt, who showed that the serum thus obtained acts equally 

 well on placental solutions and on all human blood. The question 

 of the action of the placenta when injected (in a fine emulsion) 

 into the tissues is of some importance in connection with a possible 

 pathology for eclampsia and the nephritis of pregnancy. Most 

 authorities (though not all) find that the animal thus treated 



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