He, an acute and original observer, statistician, and scientific man, properly so called, did not require to be instructed as to the lamentable results which the premature death of millions causes to the surviving relatives--results so eloquently and so correctly depicted by the illustrious Quetelet in his work on Man.[4] Of all this he was well aware, and a consciousness of such a condition of humanity, and a firm belief in the opinion that the cause lay in some defect in our social system, remediable by human means, led to those inquiries on which the late Dr. Macculloch based his theory of a universal malaria the cause of most diseases--a theory now adopted in its entirety by a large section of the medical faculty, and by the English Government of the present date. [4] Quetelet, “Sur l’Homme.” The theory or theories of Macculloch,[5] as expounded by himself, amounted in fact to this--that a poison, which may be called malaria, is generated by vegetable and animal substances whilst undergoing decomposition or putrefaction, and that to the presence of this poison may be traced most of the diseases afflicting civilized man. In a neglected drain or sewer he saw the cause of typhus, of agues, of skin disease, neuralgias, &c. [5] The late Dr. Macculloch was a distinguished geologist in the employment of Government, representing in himself the department which has now swelled out into the Metropolitan School of Practical Geology, the Museum of Practical Geology, Jermyn-street, the geological department in connexion with the Ordnance, &c. &c. He resided mostly in London, and moved in the best circles. Though a strictly scientific man, he was a professor also of the conjectural art, having been educated as a medical man. Soon after publishing his first essays on malaria, thrown out as feelers to the profession and the public, he had his misgivings as to the safety of the course he was pursuing. To denounce open sewers, undrained streets, untrapped cesspools, and overflowing dead-wells, was clearly an attack on the proprietors of London houses; and he called one morning in great haste on a distinguished barrister, to consult him as to the possibility of a passage in one of his essays being construed into a ground for an action for libel! How changed now are the views of society in respect of all such matters.