[Verse: "And God said, Let us make man in our own image, after our likeness; and let them have dominion over the fish of the sea, and over the fowl of the air, and over the cattle, and over all the earth, and over every creeping thing."--GEN. I.] 903. _Why, since all the substance of the body undergoes change, do we preserve the same features throughout our lives?_ Because our substance changes in the _minutest atoms_; and each separate atom has a life of itself, the maintenance of which preserves the _unity and permanence of the whole_. 904. _Why do moles upon the skin continue permanent, while bruises and wounds disappear?_ Because moles are themselves _organised formations_, and repair themselves just as any other part of the body does. But bruises and wounds are the result of _accidental disturbances_, which in course of time become removed. 905. _Why do the marks of deep cuts sometimes remain?_ If the cut is so deep and serious as to destroy the _system of vessels_ which supply and repair the part, then it is evident that they cannot work so perfectly as when in their sound condition. Their functions are, therefore, interfered with, and instead of having flesh uniform with the other parts of the system; there results a _scar_, or a wound _imperfectly repaired_. 906. _Why when we hold our hands against a candle-light do we perceive a beautiful crimson colour?_ Because the fluids and vessels of the body are in some degree transparent, and the thin textures of the sides of the fingers allows the light to pass, and shows the beautiful crimson colour of the blood. If the web of a frog's foot be brought in the field of a good microscope, and set against a strong light, the blood may be seen in circulation, with the most wonderful effect. Each vessel, and every globule of blood, can be seen most distinctly, and the junction of the arteries and veins can be clearly traced. The little boats of nutrition may be seen chasing each other in rapid succession, and when the animal exerts itself to escape, the flow of the blood increases; and not unfrequently, under these circumstances of agitation, have we seen two or three blood discs struggling together to enter a vessel that was too small for them. Again and again they have endeavoured to find a passage, until one of them happening to slip forward, got away, followed by the others! [Verse: "Know ye that the Lord he is God: it is he that hath made us, and not we ourselves: we are his people, and the sheep of his pasture."--PSALM C.] 907. _Why does the flesh underneath the nails look red?_ Because the transparent texture of the nails enables us to see the colour of the _vascular structure_ that lies underneath the skin. _Vascular_.--Full of vessels. In this instance, full of capillary blood-vessels. 908. _Why have we nails at our fingers' ends?_