and most important in the whole range of science; and it will need but a little study of such a book as Harvey’s “Algæ,” to show the wise man that he who has comprehended (which no man yet does) the mystery of a single spore or tissue-cell, has reached depths in the great “Science of Life” at which an Owen would still confess himself “blind by excess of light.” “Knowest thou how the bones grow in the womb?” asks the Jewish sage, sadly, half self-reprovingly, as he discovers that man is not the measure of all things, and that in much learning may be vanity and vexation of spirit, and in much study a weariness of the flesh; and all our deeper physical science only brings the same question more awfully near. “Vilior algâ,” more worthless than the very sea-weed, says the old Roman: and yet no torn scrap of that very sea-weed, which to-morrow may manure the nearest garden, but says to us, “Proud man! talking of spores and vesicles, if thou darest for a moment to fancy that to have seen spores and vesicles is to have seen _me_, or to know what I am, answer this. Knowest thou how the bones do grow in the womb? Knowest thou even how one of these tiny black dots, which thou callest spores, grow on my fronds?” And to that question what answer shall we make? We see tissues divide, cells develop, processes go on—but How and Why? These are but phenomena; but what are phenomena save effects? Causes, it may be, of other effects; but still effects of other causes. And why does the cause cause that effect? Why should it not cause something else? Why should it cause anything at all? Because it obeys a law. But why does it obey the law? and how does it obey the law? And, after all, what is a law? A mere custom of Nature. We see the same phenomenon happen a great many times; and we infer from thence that it has a custom of happening; and therefore we call it a law: but we have not seen the law; all we have seen is the phenomenon which we suppose to indicate the law. We have seen things fall: but we never saw a little flying thing pulling them down, with “gravitation” labelled on its back; and the question, _why_ things fall, and _how_, is just where it was before Newton was born, and is likely to remain there. All we can say is, that Nature has her customs, and that other customs ensue, when those customs appear: but that as to what connects cause and effect, as to what is the reason, the final cause, or even the _causa causans_, of any phenomenon, we know not more but less than ever; for those laws or customs which seem to us simplest (“endosmose,” for instance, or “gravitation”), are just the most inexplicable, logically unexpected, seemingly arbitrary, certainly supernatural—miraculous, if you will; for no natural and physical cause whatsoever can be assigned for them; while if anyone shall argue against their being miraculous and supernatural on the ground of their being so common, I can only answer, that of all absurd and illogical arguments,