Platearius, and the other earlier modern writers, describe the semi-tertian in nearly the same terms as the ancients. It is a species of fever still occasionally met with in warm climates. (See Littré’s Hippocrates, t. ii, 569.)
SECT. XXXV.—ON EPIDEMIC DISEASES.
We call those diseases epidemic and common, that attack many persons together; which, having a common origin, have also a common cause. Common diseases are produced by common food of a bad quality, drinking of bad water, inordinate fatigue, the want of the customary exercise, deprivation or repletion from the prevalence either of a famine or of great abundance. The nature of the country will also often occasion common diseases, either from its lying adjacent to marshes, or to some deep pit, which emits a deleterious and pernicious exhalation. These things are constantly occurring. But the atmosphere which surrounds us may alter the temperaments, by being hotter, colder, or more humid than ordinary. For to other causes we are not all exposed together, nor do we come in contact with them for the whole day; but the ambient air is diffused around all, and is inhaled by respiration. Now, the bodies of animals must undergo a change along with these changes as to temperature. He, therefore, who is acquainted with these matters, will not only be able to predict the diseases which are to arise from every state of the atmosphere, but will be able also to prevent them by substituting a counteracting regimen to the intemperament of the air. Wherefore, those bodies which are disposed to a certain disease, from a peculiar intemperament, will be affected by a similar temperature of the surrounding air. But those of an opposite temperament to the atmosphere will not only not be hurt but will be improved; the excess of their intemperament being overcome by the opposite excess. He that is acquainted with these things will preserve the health, by superinducing the contraries to the constitution of the body; sometimes perhaps using refrigerants, and sometimes heating things, cooling with water, using restricted exercise and food, and plenty of dilution; and warming, by means of increased clothing, exercise, more food and less drink. And, by kindling a great pile, one may change the air from a humid state to that which is dry and hot, as they say was done by Acron of Agrigentum.
Commentary. This Section is mostly taken from Oribasius (Synops. vi, 24, and Euporist. 1.)
The works of Hippocrates contain many interesting remarks on the origin and nature of epidemics. He states that diseases in general may be said to arise either from the food we eat or the air we breathe. When, therefore, a disease seizes on a multitude of persons of different ages, sexes, and habits, he justly infers that it must arise from the latter cause. (See de Flatibus, Epidem. cum Commentariis Galeni.) The fevers described by Hippocrates, in his ‘Books of Epidemics,’ are in general intermittent and remittent fevers. In his first and third books he describes forty-two cases of fever, twenty-five of which had a fatal termination. They had evidently been selected from a larger number. The descriptions are rigidly confined to a detail of the characters of the season and the symptoms of the epidemic. In general, scarcely any remedial means are mentioned. In some of the cases slight exanthemata speedily disappearing are mentioned among the symptoms. These are more likely to have been petechiæ than the typhous eruption. It is reported of Hippocrates, that, like Acron of Agrigentum, he changed the morbific state of the atmosphere at Athens by kindling fires. (Galen, Therap. ad Pison; Aëtius, v, 94.) Acron’s method of purifying the atmosphere is mentioned by Plutarch (de Iside et Osiride.) For an account of Acron, see Fabricii (Biblioth. Græc. xiii, 32); Conringii (Introduct.) and Mangeti (Bibl. Med.) Pliny says of fire as a corrective of the state of the atmosphere, “Est et ipsis ignibus medica vis. Pestilentiæ, quæ solis obscuratione contrahitur, ignis suffitu multiformiter auxiliari, certum est. Empedocles et Hippocrates id demonstravere diversis locis.” (H. N. xxxvi, 69.) With the same intention Simeon Seth proposes fumigations with frankincense. The historian Herodian relates that fumigations with aromatics were recommended as a preventive of the plague. (i.)
Galen, in like manner, attributes the origin of epidemics to the state of the atmosphere in a great measure, but also holds that the nature of the country may contribute; as, for example, its vicinity to a gulf like the Charonian, from which miasmata are exhaled that taint the air and occasion diseases. In many passages of his ‘Commentary on the Epidemics’ of Hippocrates, he states that epidemical diseases arise from the condition of the country in which they prevail. Lucretius accounts for the prevalence of epidemical diseases upon similar principles:
“Atque ea vis omnis morborum, pestilitasque,
Aut extrinsicus, ut nubes nebulæque superne
Per cœlum veniunt, aut ipsâ sæpe coorta
De terrâ surgunt, ubi putrorem humida nacta est,