In the seven plagues, miraculous operations of the Deity consisted in the unusual manifestation of phenomena, but which in their effects are recognizable as of clear and definite import. The miracles here are,--in the _mode_ of producing the swarms of frogs, locusts, &c. but they are manifest and unmistakeable _causes_ of plague and famine; in the other three, on the contrary, we witness only the effects, the causes are hidden from us; we may, therefore, as in current events, legitimately investigate the subject, and what better course can be adopted than that which classifies the traditionary past with all subsequent history. Presuming such a method of research to be admitted, I have assumed that as {39} the _causes_ of the seven plagues have been distinctly given, the others, though only mentioned in their effects, were due to causes of a nature in some way to be compared with their concomitants, that is to say, if a special intervention of the Deity brought about a miraculous appearance of frogs, lice, &c. there is but little reason to doubt that some other agent was miraculously multiplied and concentrated to induce the murrain, engender the blain, and smite the first-born: as if to lead us into this enquiry, on the visitation of the blain in man and beast, the Bible History tells us that Moses threw ashes of the furnace, which became a dust throughout all the land of Egypt; we cannot imagine that this simply as ashes could have caused the blain, we may conclude that by some special miracle, either the ashes were converted into a specific form of matter capable of inducing the effects recorded, or that an independent septic matter was generated for the purpose. If the latter, the act of throwing the ashes of the furnace into the air may have been intended to signify that the extremely minute division of the particles when thus cast into space, typified the inscrutable and hidden nature of the matter endowed with such marvellous properties.[16] {40} Further on in the book of Leviticus are passages which I cannot forbear transcribing, for they point out to us most indubitably a line of enquiry in reference to diseases of a contagious nature.