FEVER. 297 



treatment described is always applied with the best 

 results. Certainly there are also fevers in this district 

 so malignant that they end in death on a first attack. 

 The fever - producing regions are indeed as a rule 

 marshy and covered with luxuriant vegetation, but 

 also highly situated dry grass -land often passes for 

 unhealthy. I have in my journeys made the obser- 

 vation, that such regions mostly bear the traces of 

 an old, highly developed civilization, as is indeed 

 also the case in the environment of Rome and in the 

 Dobrudja, which in old times was styled the granary 

 of Rome. Fever breaks out in those regions with 

 special severity, when the soil is stirred up. The 

 fever- germs must have been gradually formed in the 

 fertile well-manured soil, which was subsequently left 

 unworked for centuries, and excluded from the air 

 by a covering of grass. Malaria accordingly represents 

 nature's penalty for interrupted cultivation of the soil. 

 This, in conjunction with the Caucasian treatment of 

 fever, led me even then to the opinion that climatic 

 fever depends on microscopic organisms, which live in 

 the blood, and whose term of life would coincide with 

 the interval between the attacks of the fever. By the 

 strong dose of quinine shortly before the attack the 

 young emerging brood of these organisms is poisoned. 

 The remarkable fact also, that people, who have 

 long lived in a fever region, are for the most part 

 secure from fever, but lose this immunity when they 

 have passed several years in regions free from it, 

 could. I thought, be explained by the assumption 



