On the Malaria of the Campa^a di Roma. 115 



very deep, and, according to Propertius, they were crossed in 

 sail boats. Livy compares the country of Rome, at the time 

 when the city was built, to a vast desert ; and Ovid says that it 

 was covered with frightful forests. 



Experience teaches us that, in all marshy and uncultivated 

 countries, the air is unwholesome; and as we know how rapidly 

 the population of Rome increased, and to what a prodigious ex- 

 tent it arrived, notwithstanding these unfavourable circum- 

 stances ; how many towns of consequence, such as Gabi and 

 others, rose up in the vicinity of these pestilential lakes ; that 

 Ostea even, founded by Ancus Martius, in a place where now, 

 in the unhealthy season, there is only a tavern supplying wine 

 and bread to the herdsmen, formerly flourished, as well as Ar- 

 dea, which at present contains only sixty inhabitants, and that 

 Lavinium is reduced to the miserable chateau of Prattica, — we 

 are compelled to inquire how the ancients sheltered themselves 

 from the pernicious influence of their unhealthy atmosphere. 



Opinions on this subject are very various. Many learned men 

 believe that the Champaign of Latium was formerly less warm 

 than at present ; because, according to Horace, the Soracte was 

 covered with snow, and, according to Livy, the Tiber was some- 

 times frozen; whence they concluded, that marshy exhalations 

 were less active and pernicious. Others attribute the absence of 

 disease in the midst of unwholesome air, to the more robust 

 constitutions of the ancients, and say with Juvenal — 



" Nam genus hoc vivo jam decrescebat Homero ; 

 Terra malos homines nunc educat atque pusillos.'* 



Others again pretend, that the air was purified by the great 

 quantity of wood that existed within and without the city, be- 

 cause it is admitted that plants absorb carbonic acid, decompose 

 it, and exhale oxygen gas. Although it may be true that plants 

 exert such an influence, this theory cannot apply to the Cam- 

 pagna di Roma, for it would lead us to a result contrary to that 

 which it is intended to establish. If the woods contribute in 

 this manner to the purification of the air in the plain of Latium, 

 they ought still to produce the same effect, since vegetation re- 

 mains as vigorous as ever. On the contrary, we find that the 

 woody districts, such as the environs of Ardea, of Prattica, of 

 Nettuno, are the most unhealthy of all, and were so in the time 



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