LYSINS, AGGLUTININS, PRECIPITINS, ETC. 249 



Ehrlich and Morgenroth, in the course of these experiments, further- 

 more succeeded in showing that the injection of isolysins into animals 

 produced antiisolysins, and that these again were strictly specific. 



The almost universal failure of autolysin production has found no 

 satisfactory explanation. It is supposed by Ehrlich and Morgenroth 

 that the failure of autolysin production may be due to a lack of 

 suitable receptors in the animal for its own cells. 



The clinical significance of the presence of isolysins and possibly of 

 autolysins in human beings, is too evident to require much discussion. 

 A practical and extremely interesting result which these investigations 

 have yielded is that of Donath and Landsteiner, 1 who discovered an 

 autolysin in the blood serum of patients suffering from paroxysmal 

 hemoglobinuria. In these cases the sensitizing substance or ambo- 

 ceptor appeared to be absorbed by the red blood cells only at low tem- 

 peratures probably in the capillaries during exposure to the cold, and 

 hemolysis subsequently resulted in the blood stream by the action of 

 complement. These observations have been confirmed by other writ- 

 ers, but the phenomenon is surely not present in all cases of paroxysmal 

 hemoglobinuria. The writers have had occasion to examine carefully, 

 several clinically typical cases with negative results. 



1 Donath und Landsteiner, Munch, med. Woch., xxxvi, 1904. 



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