"On mules and dogs the infection first began,
And last the vengeful arrows fix'd in man."

In our own day epizoöties have been observed as occurring antecedently to and concurrently with epidemics.

It is fortunate that we are enabled to arrest the ravages of pestilential disorders, and are even competent to prevent an epidemic by early extinguishing the germs of disease, while at the same time we are unaware of the exact character of the subtile agents we are destroying. The miasm of cholera and the malaria of yellow fever, except in a very few localities, offer only occasional opportunities of examining their essential qualities; but paludal exhalations from time immemorial have afforded ample occasion for study over a large extent of territory and during a part of every year.

The Pontine marshes spread infection in the territory of the Volschi, as they contaminate the same tract of country for its modern inhabitants. The troops engaged in the wars of the classical era doubtless suffered from malarial influences precisely similar to those which have desolated our own forces on the shores of the Chickahominy and Pamunkey. But the Italian morass, thirty miles in length and eight in breadth, has at times been partially converted into inoffensive and fertile plains by the thorough system of drainage enforced during the reigns of Augustus, Nerva, and Trajan, and during the pontificate of Pius the Sixth. At other periods engineering resources were neglected; rich fields degenerated into impassable and noisome bogs, while the inhabitants

of the environs lost their ruddiness and acquired an anæmic pallor.

Had the efforts towards reclamation been persistently made from the time of their inception by the Consul Cethegus, a baneful spot could have been permanently obliterated; stagnant waters could have been collected into running streams; quagmire converted into loam, and the low vegetation of a vast fen metamorphosed into genial fruitfulness. The earth itself would have become as magnificent a monument of the philosophy and grandeur of ancient Roman civilization as have been the classical literature and massive architecture of the historical period alluded to.

In modern times there have been imitations of the ancient methods of draining in numerous localities, but nowhere perhaps has any much more extended and more promising scheme been attempted than in the one to which I have especially referred. The benefits to be derived from the construction of arti ficial water-courses, so arranged as to draw off exces sive surface moisture, can scarcely be over-estimated; such benefits redound to the physical welfare of mankind and to the agricultural interests of a State.

It is painful, however, to acknowledge inability to detect, either chemically or microscopically, the subtile agent engendered in marshy and littoral situations, and to confess ignorance respecting the modus operandi of the poison upon the human economy. We peruse the most elaborate monographs relating to these subjects without deriving from them any precise scientific knowledge, and in despair almost feel inclined to turn for information

4

to the paper by Samuel Pickwick, Esq., read before the Pickwick Club, and entitled "Speculations on the Source of the Hampstead Ponds, with Some Observations on the Theory of Tittlebats." A field of inquiry is still open in the direction to which I have made reference. Let us not be satisfied in conquering a foe of whose character we are ignorant. We know its numerous lairs-let us search its haunts among the ignes fatui till we entrap the poison, and announce its properties as found, either in animalcules or vegetable fungi, or in inorganic solid, liquid, gas, or vapor.

In no respect, perhaps, is the astuteness of the ancients more remarkably exhibited than in their views concerning solar and lunar influence upon mankind. Some of the phenomena they ascribed to such agency we recognize as due to the same cause, but explain their occurrence in a different manner; while others, asserted to have been observed in earlier days, we scarcely admit to have noted.

The Psalmist, in predicting the blessings of a future condition, has said :-"The sun shall not smite thee by day, nor the moon by night." The Scriptures record two cases of sunstroke-one the son of the Shunammite, who, being "in the field with the reapers, said unto his father, My head, my head! And when he had taken him to his mother, he sat on her knees till noon and then died." The second: "And Manasses was her husband, of her tribe and kindred, who died in the barley harvest; for as he stood in the field, overseeing them, and bound sheaves, the sun came upon his head, and he died in his bed in the city of Bethulia." I do not recall any instances in holy writ of injury induced by the moon.

Sunstrokes have been observed in all periods of the world and are encountered in our own day. The early philosophers were no less keen, however, in remarking the salutary as well as the insalutary influences of the solar ray. The importance of fresh air and of exposure to the sun in genial weather was fully understood, and solar air-baths, in some instances, were constructed on the house-tops, to which the inmates might resort for recreation and health. The ancients were of course ignorant of the precise nature of the atmosphere and of the sun's ray, but had observed their beneficial action upon animals. It has been reserved for modern times to give the explanation. We have thought until quite recently that we understood the composition of the air and the nature of light, but within comparatively a few years the experiments of Fraunhofer, Bunsen, and Kirchhoff, by means of the spectroscope, have exhibited the fact that the incandescent sun emits into its atmosphere iron, nickel, sodium, calcium, magnesium, chromium, etc., and we have consequently learned that the solar ray is more complex than was hitherto imagined. Is it not reasonable to suppose that in addition to any salutary chemical action of the sunlight upon mankind, that the vapor of iron, etc., may be absorbed through the lungs and skin, and be made to play an important part in the vital economy?

Thus it is that certain phenomena of nature, correctly observed by the ancient philosophers, are scientifically explained by the sages of the nineteenth century.

By the same manner of spectrum analysis, Miller, Huggins, Father Secchi, Alexander Herschel, and

others, have informed us of the composition of the fixed stars, nebulæ, comets, meteors, etc., while the chemists employ a similar method to decipher the nature of various terrene substances, and have thereby detected several ultimate inorganic elements which had previously escaped recognition.

Lunar influence, from a remote antiquity, has been regarded as being unfavorable upon mankind. The term lunacy, still employed in our nosology, is indicative of this olden regard. The periods of new and full moon were believed to be inimical to health, and during the course of diseases induced unfavorable crises. These views, becoming associated with the vagaries of the astrologists, were, for the most part, discarded, but there have been a few in modern times who have clung to the dogma. In India a disease occurs known as coup de lune; and it is very popularly believed here and elsewhere that repose in the moonlight is injurious. Milton, in alluding to this belief, speaks of

"Demoniac frenzy, moping melancholy,

And moon-struck madness."

Poe, in illustrating the desire to escape exposure to the moonlight during sleep, has prettily said,

“Neath blue-bell or streamer,

Or tufted wild spray,
That keeps from the dreamer
The moonbeam away."

How much either of truth or of fancy there is in such views is as yet undecided. Dr. Winslow, of England, has recently directed special attention to the subject of lunar influence as a cause of disease,