116 Journal of the Mitchell Society ^December 



produce in the rabbit effects that are alike in both character 

 and degree. 



The dose of hematin remains as the one factor to which it 

 is possible to attach some degree of uncertainty, but even here 

 the author feels that the range of experimental conditions has 

 been kept within the bounds of legitimate analogy with condi- 

 tions existing in the human subject of malarial infection. 



Finally, the most conservative estimate of the value of such 

 experiments points strongly to the fact that we have at least a 

 potentially toxic substance in the pigment hematin as liberated 

 by the malarial parasite into the circulation of the human host. 



There is also abundant evidence to show that the action of 

 hematin is not confined to the paroxysmal phenomena of ma- 

 laria, but that other features of the disease may find their ex- 

 planation in the action of this pigment. For the present, how- 

 ever, it seems advisable to confine the discussion to this one 

 phase of the question. 



CONCLUSIONS. 



1. Alkaline hematin in doses commensurate with the 

 amounts of hematin liberated in the human circulation by the 

 segmentation of the malarial parasite, produces, when injected 

 intravenously into the rabbit, a paroxysm which is character- 

 ized by a short prodromal stage, a stage of chill and rising tem- 

 perature, and a hot stage. In their details the phases of this 

 paroxysm are practically identical with the corresponding ones 

 in the paroxysm of human malaria. 



2. The phenomena in human beings infected with malaria 

 are, at least in part, directly referable to the toxic action of 

 this malarial pigment. 



University of North Carolina. 



