and consequently tasteless, melting at a temperature twenty-eight degrees above the boiling point of water, and dissolving in liquid bi-sulphate of carbon. This is the ordinary suit of properties in which sulphur presents itself. But we know it also in quite another form. If we place a little of it in a glass flask over a lamp, when the heat reaches two hundred and forty degrees, it fuses into a transparent, nearly colorless, liquid. If now we pour it into cold water, it reverts to its ordinary solid state, a yellow, half-crystalline, solid, brittle mass. But instead of pouring it out, suppose we keep it over the lamp with the continuous addition of heat. When the temperature has risen. to about three hundred and twenty degrees, the limpid fluid changes its aspect, the particles link together, and the mass becomes viscid or thick, so that the flask may be completely inverted, and it will not run out. If we push the temperature still higher, the particles again unlock; fluidity again ensues, but now the liquid is of a dark brown, or amber color; it has assumed another state, and we have allotropic sulphur. If, then, we pour it again into cold water, we have no longer the yellow, brittle body with which we began, but a soft, tough, flexible substance, somewhat like India-rubber, which may be drawn out into elastic threads. The sulphur has lost its attributes of hardness, brittleness, crystalline structure, fusibility, it does not melt so readily as before, and its solubility, for it no longer dissolves in bisulphide of carbon. And with this total revolution of its nature, its physiological relations have been changed, it has lost its old and acquired a new medicinal character.

This is a fair example of the phenomena, and it is certainly full of significance. Dr. Faraday remarks: "In view of the facts, the philosopher cannot forbear asking himself the question, in what does chemical identity consist? In what will these wonderful developments of allotropism end? Whether the socalled chemical elements may not be, after all, mere allotropic conditions of fewer universal essences. Whether, to renew the speculations of the alchemists, the metals may not be so many mutations of each other by the power of science mutually convertible.” There was a time, when this fundamental doctrine of the alchemists was opposed to known analogies; but it is now, says Dr. Faraday, no longer opposed to them, but only some stages beyond their present development.

But we are not dealing with empty facts, or mere barren curiosities of science. The new phenomenon has vital bearings upon our living economy; it is a high factor in physiological problems; a key to otherwise unexplained mysteries of our complex and wonderful nature. To understand this, we must first glance at the great general laws of the human constitution. The body of the grown man, as I have elsewhere written, presents to us the same unaltered aspect of form and size, for long periods of time. With the exception of furrows deepening in the countenance, an adult man may seem hardly to change for half a hundred years. But this appearance is altogether illusory, for with apparent bodily identity, there has been an active and rapid change, daily and nightly, hourly and momentarily, an incessant waste

and renewal of all the corporeal parts. A waterfall is permanent; and may present the same aspect of identity from generation to generation; but who does not know that it is merely an abiding form, and is made up of watery particles in a state of swift transition. The flame of a lamp presents to us, for a long time, the same appearance; but its constancy of aspect is caused by a ceaseless and orderly change in the place and conditions of the chemical atoms which carry on combustion.

Just so with man; he appears an unchanging being, endowed with permanent attributes, but he is really only an unvarying form, whose constituent particles are forever changing. Few persons have any conception of the rate at which changes go on in their bodies. The adult man introduces into his system, in the course of a year, some eight hundred pounds of solid food; about eight hundred pounds of oxygen gas from the air, and fifteen hundred pounds of water; making a ton and a half of matter, solid, liquid, and gaseous ingested annually. The living organism of man is thus a whirling vortex of incessant transformation. The heart beats sixty or seventy times a minute, and every pulsation sends forward two ounces of blood, so that the whole amount in the system rushes through the lungs once in two minutes and a half, or twenty times in an hour. Hence all the blood in the body travels through the circulatory route six or seven hundred times a day; or a total movement through the heart of ten or twelve thousand pounds of blood in twenty-four hours. Thomas Parr died one hundred and fifty-two years old. He

therefore drank upwards of one hundred tons of water; ate sixty tons of solid food; and inspired one hundred and twelve thousand pounds of oxygen gas from the atmosphere to act upon that food. If all the blood-which passed through his heart in that long period could have been accumulated and measured as one mass, by forming a procession of vehicles each taking a ton and occupying two rods of space, such a procession would have attained the enormous length of two thousand miles.

Now all this is for a purpose. The living being is the result and representative of change on a prodigious scale, but it is for a fundamental and all-controlling reason. The life, activity, susceptibility and multiform endowments of the bodily organism, depend entirely upon these internal transformations. All parts perish in exercise, and perish at a rate proportioned to the degree and duration of the exercise. There is an incessant dying of atoms in all parts of the fabric. Half a thousand muscles minister to our purposes and work, but at each contractile spring, hosts of their constituent particles die. So too with the nerve cords: they transmit impressions and impulses only at the cost of destruction of nervematerial. The strains of music pass into the sensorium, but the auditory nerve must perish that we may revel in the delights of harmony. The universe pours itself inwards through the eye, but the retina dies in transmitting the pictorial impressions of beauty up to the throne of the mind. And so also by reflection and emotion the brain itself is disorganized and dissolved. In the processes of intellec

upon

decom

tion, myriads of cerebral atoms expire. Mr. Wilson has happily observed that Jeremy Taylor foreshadowed a great physical truth when he said long ago, that "while we think a thought we die," but no modern science amends the statement and teaches that not only whilst but because we think a thought we die. Interstitial destruction is thus the prime condition of life. It is said, with reference to the casualties to which man is everywhere exposed, that "In the midst of life we are in death," but, physiologically, this is a still profounder truth; we begin to die the moment we begin to live. But the death of the old implies the birth of the new; parts perish and are reconstructed nutrition waits position, and thus destruction and renovation are indissolubly connected the constant terms of the vital equation. As the disorganized products of change escape to the outward world, matter newly organized stamped with vitality in the mint of the universe is perpetually introduced to rebuild the failing textures. The subtile alchemy of life is thus of a twofold nature. The solid fabric is continually melting and dissolving into liquid and exhaling away into air; while vapors are condensing into liquids, and liquids congealing into solids. Blood is liquefied muscle, sinew, nerve, brain and bone; while bone, brain, nerve, sinew and muscle are solidified blood; and at every instant flesh is fusing into blood, and blood consolodating into flesh. And the red river of life flows alike to all parts, yielding its various secretions, tears, saliva, gastric juice, milk, and bile, and furnishing all the special constituents required by the