is that science ministers to our service; and how much more pleasing is it to contemplate the lightning, with the philosopher, as an agent destroying the elements of pestilence, and restoring the healthfulness of the air we breathe, than with the romancer, to see in it only the dreaded aspect of a demon of destruction. The laws which regulate the spread of a pestilence are unknown. The difficulties of the investigation are great, but they are by no means insurmountable. A plague passes from the east to the west across the world--it spreads mourning over the gayest cities, and sorrow sitteth in the streets. The black death rises in the Orient: it goes on in unchecked strength, and only finishes its course when it has made the circuit of the civilized world. The cholera spreads its ebon wings--mankind trembles--watches its progress, and looks upon the path which is marked by the myriads of the dead, who have fallen before the dire fiend. The diseases pass away--the dead are buried, and all is forgotten. The rush and the riot of life are pursued: and until man is threatened with another advent, he cares not to trouble himself. Accompanying the last visitation, there appear certain peculiar meteorological conditions, which point a line of inquiry. It may or may not be the path which leads to the truth, but certainly its indications are worthy of careful examination. It may be asked, can weak man stop a pestilence; can a mortal’s puny hand retard the afflictions of the Almighty? The question asked--it must be answered in reverence, yet without fear. No human power can produce a change in the physical conditions of the earth, or of the air; and if our diseases are connected with those changes, as beyond all doubt a number of them are, they lie above man’s control. But when there are indications that causes secondary to these are producing some dire effect, and when we know that these secondary causes may be modified, it is sufficient evidence to prove that man is permitted to control thus far the afflictions which are sent to try his powers. We find a disease winging its way from lane to alley and closed court, sweeping with destructive violence its way through damp cellars and crowded attics; it is rife with mischief along the banks of reeking ditches, and on the borders of filthy streams. Certain it is, therefore, that some ultimate connexion exists between the conditions of dirt and this speedy death. Can science tell of these? has it yet searched out the connecting link? Let the question be answered by a few facts. When the cholera first made its appearance, and subsequently, it has been observed that the electrical intensity of the atmosphere was unusually low. The disease has departed, and it is then found that the electricity of the air has been restored to its ordinary condition. This appears to show some connexion; but how do these conditions link this physical force with the ditch-seeking disease?