74 DISEASES DUE TO PROTOZOA 



sporulale every tliirty-six lo forty-eiglu liours. The}' give rise to 

 severe local symptoms as well as general ones, the local svmptoms 

 differing as to the part attacked, hence trouble may arise owing to a 

 mechanical blocking of the capillaries of the brain, &c., or to the local 

 intense action of the toxin, or to both of these causes in one individual. 

 There result, therefore, the pernicious manifestations of malaria, e.g., 

 in the brain, causing coma or paralvsis; in the ]:)ancreas, causing 

 ha?morrhagic pancreatitis, &c. 



These symptoms are known under the term subtcrtian malaria. 



Each type of parasite may cause irregular symptoms at first, but 

 each settles to grow, sporulate and to rupture their host cells at the 

 same time, due probably to the fact that the toxin liberated may kill 

 off the immature forms. 



It is to be remembered that double and triple broods are known of 

 the same parasite in the same individual. 



The parasites also have a ha.miolytic action, destro\'ing the red cells, 

 hence throwing more work upon the alreadv overtaxed liver. This 

 leads to excessive bile formation A\ith diarrluva and bile in the urine. 

 If this detritus is excessive, the liver, not being able to convert the 

 haemoglobin into bile, some of it will pass through causing haemo- 

 globinuria. 



An antitoxin is formed which seems to quicklv neutralize this 

 haemolytic toxin, and may lead possiblv to a cure of the disease. 



Starvation diminishes the power of the bodv cells to manufacture 

 sufficient of this antitoxin, hence relapses ma\' occur. 



MORPHOLOGY AND HISTOLOGY. 



Each parasite has an intracorporeal or human cycle, also an extra- 

 corporeal or mosquito cycle. Some affirm that there is a latent phase 

 also. 



INTRACORPOREAL OR HUMAN CYCLE. 



This human life span is forty-eight or seventy-two hours according 

 to the type of parasite. A few hours before a febrile paroxysm the 

 parasites may be seen in the red cell as a pale, ill-defined disc occupy- 

 ing part or the whole of the red cell in the benign tertian form, dis- 

 tending the cell in many cases. 



Scattered irregularly about this pale body are many black or 

 reddish-black dots excreted by the parasite. These are called haemozoin 

 {melanin). 



These parasites concentrate into several central blocks, around 

 which the parasite, becoming segmented, arranges its segments or 

 spherules. The cell ruptures, the spherule escapes into the liquor 



