APPENDIX C. 



MALARIAL FEVER. 



THE organism which is now almost universally believed to 

 be the causal agent in malarial fever was discovered by 

 Laveran in 1880. This organism does not belong to the 

 vegetable but to the animal kingdom ; it is not a bacterium 

 but a protozoon. It is usually known as the hczmatozoon or 

 plasrnodium malaria. The use of the term plasmodium is, 

 however, incorrect. Laveran's discovery received con- 

 firmation from the independent researches of Marchiafava 

 and Celli, and later from the researches of many others in 

 various parts of the world. Valuable additional information 

 on the subject was supplied by the work of Golgi, who 

 specially has the credit of first distinguishing certain varieties 

 of the organism in the different types of malarial fever. In 

 this country valuable work on the subject has been done 

 by Manson. Regarding the invariable presence of this 

 organism in the blood, and the cycle of changes which it 

 undergoes in relation to the paroxysms of fever, practically 

 all are agreed. On the other hand, some doubt still 

 prevails regarding certain stages in its development, and 

 especially regarding the number of varieties of the organism 

 and their relations to one another. We shall first give an 

 account of the different forms in which the organisms are 

 met with, and afterwards state some facts with regard to 

 the varieties which have been described. The description 

 will be simplified by stating that the parasites in all the 

 types of malarial fever pass through a definite cycle of 



