THE PATHOLOGY OF MALARIA 639 



parts played by the development of artificial immunity on the 

 one hand, and the existence of a natural immunity on the other, 

 in relation to insusceptibility to malaria. 



Our knowledge on the relationship of blackwater fever to 

 malaria is also in an unsatisfactory condition. Blackwater fever 

 is a condition often cccurring, especially in Europeans, in tropical . 

 countries. It is characterised by pyrexia, darkly-coloured urine, 

 — the colour being due to altered haemoglobin pigment, — delirium 

 and collapse, frequently ending in coma and death. By some 

 the condition has been looked on as a separate disease, by others 

 as the terminal stage of a severe malaria. With regard to the 

 former view, no special parasite has yet beep demonstrated. 

 Stephens sums up the evidence for the second view by saying 

 that malaria, apart from the occurrence of blackwater fever, is a 

 relatively non-fatal disease ; that in the great majority of cases 

 there is direct or indirect evidence of the subject of the condition 

 having suffered from repeated attacks of malaria ; that while in 

 all cases there must be an agent at work causing hemolysis, 

 there is evidence that in many cases there is the possibility of 

 that agent being quinine. Christophers and Bentley came to 

 the conclusion that the essential feature in blackwater fever 

 is an extracellular destruction of red corpuscles in the blood 

 plasma, a lyssemia as they call it, and that this is not directly 

 due to parasitic, osmotic, or chemical actions, but to a specific 

 hemolysin arising in the body as the result of the repeated 

 blood destruction. They have shown, for example, that the 

 addition of fresh serum (complement) to the red corpuscles of 

 blackwater fever, as well as of malarial, patients may produce 

 ysis, this apparently being due to a substance corresponding 

 to immune-body united to the corpuscles in question. The 

 development of this hsemolysin (autolysin) results from the ex- 

 tensive and repeated destruction of red corpuscles by the malarial 

 parasite. Thus though the latter is not the immediate cause 

 of the lyssemia, which is the essential feature of blackwater 

 fever, it is the means of inducing the development of the 

 hsemolysin. If this view of the process is found to be correct, 

 it would of course explain the relationship of malaria to the 

 condition. They also consider that in. the conditions men- 

 tioned, i.e., where there has been repeated destruction of an 

 individual's corpuscles by the malarial parasite, the occurrence of 

 lyssemia may be precipitated by an acute attack of malaria 

 especially when under certain circumstances this is associated 

 with the administration of quinine. On this- view, however, it 

 still remains to be determined whether the lysis at the onset of 



