CHAPTEE X. 



MALARIA. 



First recognised as a parasitic disease by Laveran — Varieties of the 

 organism — Manson's mosquito theory — Tertian, quartan and 

 summer-autumn fevers — Sporulation — Crescents — Surgeon-Major 

 Boss on the value of the microscope as an aid to diagnosis — Exami- 

 nation of the blood for the parasite — Permanent preparations — 

 Staining — Eeferences to recent literature. 



It was first shown by Laveran, in the year 1880, that 

 certain amcsboid organisms were to be found in the blood 

 of malarial patients ; and as the organisms described 

 by him were crescent- shaped, they received the name 

 'Laveran's sickles.' It has since been found that the 

 organisms described by him occur chiefly after an attack 

 of malarial fever, and are rarely present in the blood 

 during the febrile period. Later on it began to be recog- 

 nised that the varying forms of malarial fever are each 

 caused by distinct varieties of parasites. 



As our knowledge of these remarkable organisms is as 

 yet very far from complete, and as there are considerable 

 differences of opinion on several important points, we shall 

 do no more than touch on the life-history of the parasite, 

 and give references to the original papers of recent date. 



It is not yet thoroughly established whether the varieties 

 of fever known as tertian, quartan, and quotidian, or 

 summer-autumn, are caused by entirely distinct parasites, 



