1915] /. Bronfenbrenner 89 



of a ferment natura) with its antigen, in vitro, is also capable of re- 

 moving the antitryptic inhibiting principle from the serum, setting 

 free the protease which, in turn, digests the globuHn fraction of the 

 serum and produces dialysable substances, 



Incidentally I wish to call attention to the fact that this auto- 

 digestion of serum may explain the mechanism of the phenomenon 

 of the complement-deviation or complement-fixation, for, in each 

 case where complement is fixed, there appear dialysable products that 

 give a positive ninhydrin test and, vice versa, wherever the Abder- 

 halden test is positive, the complement (as can be proved) is inac- 

 tivated. 



The auto-digestion of serum, induced by the removal of anti- 

 trypsin in Jobling's experiments, can be stopped by returning non- 

 saturated fatty acid to the serum. The auto-digestion of the serum 

 in the Abderhalden test (which is due to the removal of the anti- 

 tryptic Inhibition from the serum of the patient, by the combination 

 of serum antibody with placenta-antigen) can also be stopped by the 

 addition of non-saturated fatty acids. According to my experi- 

 ments, moreover, self-digestion of the serum results in the produc- 

 tion of a toxic substance which appears to be identical with Fried- 

 berger's anaphylatoxin and, when occurring in vivo, is probably the 

 cause of eclampsia. I am inclined to think from the results of some 

 of our experiments, that here we have the clue to possible prevention 

 of this much dreaded occasional accompaniment of child-birth. 



In Short, the Abderhalden reaction is specific, but depends not as 



Abderhalden believes, on the presence of specific enzymes, but on the 



presence in the blood of pregnant women of the specific antibody that 



Combines with placenta antigen, and thus sets free the only 



proteolytic enzyme which is always present in the serum of every 



animal. When considered from this point of view, the Aberhalden 



test should be positive wherever the complement-deviation test is 



positive. I have obtained, in many instances, a positive reaction 



with the sera of syphilitics, using pure lipoid antigen, in which the 



only source of protein cleavage products was the serum of the 



patient. This again proves that not the Substrate, but the serum 



itself, is digested in the Abderhalden test. 



Western Pennsylvania Hospital, 

 Pittsburgh, Pa. 



