136 THE SCIENTIFIC MONTHLY
elsewhere. For the rest, through the supreme goodncFs of God, I have neTcr been called upon to treat the plague, and, for this reason, I gladly refrain from expressing a definite opinion concerning pestiferous worms in the blood, as being a thing I know almost nothing about.
Lancisi also shows that good drainage drives away fevers. The great aqueducts and drains of the ancient Romans had apparently been de- signed for this purpose, and, through the Middle Ages up to the nine- teenth century, the Papacy made many eflPorts to drain the Pontine Marshes and to cultivate the deserted Campagna, methods of sanitation which Ross summarizes as the " principle of mosquito reduction/* Torti, at Modena, introduced cinchona bark into Italian practise, and by its use differentiated the pernicious forms, which do not yield to treatment, and of which he gave the classical account (1712). He also introduced the term "malaria," from the Italian waZ'am (bad air). The expressive term, first employed in English by John Macculloch, in bis treatise "Malaria" (1827), epitomizes the earlier theory of its causation, viz., that it is due to miasms or effluvia, t. e., gaseous emanations given off by stagnant water or even by the earth itself.
The next step in the history of malarial fever was the discovery of the parasites causing the disease. The theory that diseases may be caused by minute living organisms, invisible to the naked eye, is also very old, as is plain from the above citation from Varro. It was first stated in scien- tific form by Fracastorius, in his treatise on contagion (1546), and later by Athanasius Kircher (1658), who investigated minute organisms with the microscope. In 1730, as cited by Professor W. S. Thayer, Thomas Fuller, an English physician of the eighteenth century, made the follow- ing quaint suggestion that malarial fever may be caused by minute organisms :
Can any Man, can all the Men in the World, tho' Assisted by Anatomy, Chymistry, and the beJ^t GlaFses, pretend positively and certainly to tell us, what particles, how sized, figured, situated, mixed, moved, and how many of them are requisite to produce a quartan ague, and how they specifically differ from those of a tertian?
Agostino Bassi, who discovered the microorganisms causing silk- worm disease, relates that the physician Basori of Milan said to him of his discovery:
I am fully persuaded of the truth of your useful discovery. For many years I have held the opinion that the intermittent fevers are produced by parasites which call forth a new paroxysm by the act of their reproduction, which occurs at more or less rapid intervals according to the diverse species. In this way, the intermittent fevers, quotidian, tertian, quartan, arise (1846).
In the meantime, Jacob Henle had published his essay "On Miasms and Contagia" (1810), stating his theory of living contagia, with refer- ence to Bassi's work; and, in 1819, Dr. John K. Mitchell published his treatise " On the Cn'ptogamous Origin of Malarious and Epidemic