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malarial affections we read of their long descent, as time 

 alone could have rendered the human race so subject to 

 them, and, as a matter of fact, their history, of every type, 

 reaches back to the earliest period of medical knowledge. 

 Whilst we are all probably more or less subject to the 

 malarial diathesis, it should not be forgotten that all are not 

 in equal measure predisposed to the action of the malarial 

 poison, for it is well-known that " during the endemic 

 prevalence of malaria, only a certain number of persons are 

 attacked by it, the majority remaining exempt, although 

 subject to the same telluric and climatic influences;" 1 and 

 this exemption is, in all probability, very frequently inherited. 

 That constitutional varieties are not to be ignored as influenc- 

 ing the liability to malaria is proved by the fact that weak and 

 anoemic persons are especially prone to be attacked, and, 

 according to Griesinger, marked differences in the character 

 of the disease may sometimes be recognised, according as 

 it occurs in subjects of a plethoric, or of an anaemic con- 

 stitution. As malaria can alone produce malarial diseases, 

 their different forms differ relatively only in degree, the 

 poison itself being subject to variations in quality and 

 quantity. These affections may, therefore, be progressively 

 arranged from the simplest to the severest forms as follows : 

 i. Quartan intermittent ; 2. Tertian ; 3. The masked inter- 

 mittent ; 4. Double tertian ; 5. Remittent ; 6. The continued; 

 and 7. The pernicious fever ; the various grades being pro- 

 portioned to the intensity of the poison. But the real fact 

 to remember is that all these varying forms are due to the 

 effect of the malarial poison on different individuals, and 

 that these individual differences may be either acquired or 

 inherited, and that even when acquired many of them may 

 be transmissible. 



1 Hertz. 



