this separation takes place, however, it has often begun to reproduce its own young, and so we sometimes see a large colony of hydras all connected together, like minute branching water weed.

After all, you may say, it is not so very wonderful that a simple animal like the hydra, which has no intestines, and scarcely any special organs whatever, should be able to reproduce its lost parts, or to multiply itself by the simple processes of growth and subsequent division. Well, then, let us take a more complex creature, and we have a remarkable example at hand in a certain marine worm called myrianida fasciata. It is an inch or two in length, tapering off gradually from the head. The body is marked with numerous rings or joints, attached to which are oar-like appendages, serv ing not only as instruments of propulsion but also as gills, or breathing organs. An intestine extends from the head in a direct course to the posterior. Blood-vessels are arranged about it like a net-work, and connect with similar vessels in the gills. It has an organ which serves the purpose of a heart, a nervous cord swollen at every joint into knots or ganglions, and, in the head, one principal ganglion, which may be considered as the brain. Its reproductive organs are situated only in the posterior rings, and are located there in reference to the peculiar mode of generation which we are about to describe. The young worm begins to grow immediately in front of the parent's tail, that is to say, between the last joint or ring and the next before the last, and is formed by the successive growth of new rings. Before it is old enough to be cast off another appears between its anterior end and the next joint of the old stock; and so on until we have six worms at once, all strung together behind the parent, and hanging, so to speak, from one another's tails. They drop off separately, in the order of their age. Now in this case, you will observe, there must be a division of several or

gans-the intestine, the blood-vessels, and the nervous cord; and each of the six young must develop a heart, a brain, and a pair of eyes. An odd result of their method of growth (the first one being formed, you will remember, not behind the parent but between her last two rings) is that the eldest offspring appropriates the tail of his mother, while his five brothers and sisters have to find tails of their own. We are here tempted to indulge in a curious speculation: this first born produces its young in the same way itself was produced, and passes on its inherited tail to the next generation. The eldest born of that generation bequeaths it to the next, and so on. What becomes of that ancestral tail in the course of years? Does it at last wear out and drop off? Does the worm that bears it die after a time without leaving any children? Or is it possible that the process of entail has been going on without interruption ever since the year one of the world, and that there may be a myrianida fasciata now living with a tail as old as creation? Not very probable, certainly; but if any solution has been offered of the great tail problem, we do not happen to have heard of it.

He cut

Professor Clark also tried various experiments upon the common flat worm, or planaria, which may be found so readily in our ponds, creeping over stones and aquatic plants, and is so easily recognized by its opaque white color, and the liver-colored ramifications of its intestine. the creature in two, and immediately after the operation the halves crawled away as if nothing had happened; the anterior part preceding an ideal tail, and the posterior one following an equally imaginary head and brain. He watched the pieces from day to day, and found that each reproduced its missing half by a slow process of budding and growth. This planaria may be cut into several pieces, and each will reproduce what is requisite to complete the mangled organism. If the tail of a lizard be broken off, a

new one will grow; and crabs, lobsters, spiders, etc., are known to replace their amputated limbs. The instances we now and then meet with of what are called monsters-twoheaded dogs, calves with six legs, and, more rarely, even double-headed human beings, are examples of the phenomenon of budding-which is very common, by the way, among fishes; and there is an animalcule called the amaba which shows a more remarkable tenacity of life than any of the other creatures we have mentioned, since you may divide and subdivide it until it is physically impossible to reduce it to particles any smaller, and yet each piece will live.

The discovery that animals may originate in so many ways independent of maternal gestation naturally suggests the inquiry whether further researches may not develop still other methods of reproduction, in which the new-born creature shall have no connection whatever with any previously existing individual. Thus we are brought back to the question which was thought to have been settled long ago, whether generation ever takes place spontaneously, as Aristotle and the old physicists supposed it did. Later naturalists, following the Italian, Redi, utterly rejected the supposition; but within the present century it has found many reputable supporters, and Professor Clark is one of them. When organic matter decays, numbers of infusoria, or microscopic plants and animals, arise in it. Where do they come from? Do the disorganized particles, set free by the process of decomposition, combine into new forms, which are then endowed with life by the direct action of Almighty power; or is the decaying substance merely the nest in which minute eggs or seeds, borne thither upon the air, or dropped by insects, find conditions suitable for their development in the ordinary natural way? The question is not easily answered. Many of these germs are so excessively minute

as to defy detection. Some of the infusoria are no larger than the twentyfour-thousandth of an inch in diame ter, and it is estimated that a drop of water might contain five hundred millions of them. It is obvious that the germs of such little creatures must be invisible even with the best microscope. The problem can only be solved by placing a portion of the decomposing matter under such conditions that any germs it may contain shall infallibly be killed and that none can possibly reach it; then, if infusoria appear, we shall know that they have been generated spontaneously. The great difficulty is in securing these conditions. For the development of the living forms we require both water and air. How are we to be certain that there are no living germs in the organic matter before we begin the experiment? that there are none in the water? that none are brought by the air? The action of heat has been relied upon for the destruction of germs in the organic matter and the water, and it has been sought to purify the air from them by passing it through sulphuric acid; but experience has shown that sulphuric acid does not kill the germs; so of course experiments performed in that way prove nothing. Professor Clark quotes a series of very delicate experiments tried by Professor Jeffries Wyman, of Harvard University, which seem to us to come nearer to proving spontaneous generation than any others with which we are acquainted. He proceeded in three different methods, as follows:

1. The organic matter, consisting of a solution of beef or mutton juice (or, in a few instances, vegetable matter), was placed in a flask fitted with a cork through which passed a glass tube. The cork was pushed deeply into the mouth of the flask, and the space above it was filled with an adhesive cement, composed of resin, wax, and varnish. The tube was drawn to a narrow neck a little way above the cork, and bent at right angles, and

the end of it inserted in an iron tube, where it was secured by a cement of plaster of Paris. The rest of the iron tube was filled with wires, leaving only very narrow passages between them. The solution in the flask was then boiled-in some cases as long as two hours-in order to kill any germs which might be enclosed, and to expel the air. The iron tube and wires at the same time were heated to redness. When the boiling had continued long enough the heat was withdrawn from beneath the flask, and the steam was allowed slowly to condense. As it did so, air flowed in between the red-hot wires, which had been kept at a temperature high enough, it was supposed, to destroy any germs in the air that passed through them. The flask was then hermetically sealed by fusing the glass tube with the blow-pipe. When opened, several days afterward, it was found to contain animal life.

2. A similar solution was placed in a flask the neck of which, instead of being supplied with a cork and tube, was drawn out and bent at right angles, and then fitted to the iron tube containing wires. The experiment was performed as by method No. 1, and with the same result.

3. That there might be no suspicion of imperfectly sealed joints, a solution was put into a flask with a narrow neck, and the neck itself was then closed by fusing the glass. The whole flask was then immersed in boiling water. At the expiration of

a few days living infusoria were found in two instances out of four.

Now these experiments undoubtedly prove that generation sometimes occurs spontaneously, provided it be true, as Professor Clark assumes, that there was no imperfection in the closing of the flasks (which we see no reason to doubt), and that the infusorial germs are destroyed by boiling. We confess that it is hard to believe they could have survived such a heat as was applied to them in these cases; but is it certain that they could not? A writer in an English review a few years ago, whom we believe to have been Mr. G. H. Lewes, announced that he had boiled certain germs an hour and three-quarters, and yet they remained perfectly unaltered. At most, therefore, we can regard spontaneous generation as a probable phenomenon.

Whether spontaneous generation, if it occurs at all, occurs by the formation of an egg from which the animalcule is hatched, or by the immediate formation of the adult, Professor Clark does not attempt to say; but the French naturalist M. Pouchet, who is one of the foremost advocates of the theory, holds that an egg is produced first. If this is true we shall have a striking correlative to the proposition with which we began this paper: not only can living creatures be developed where no egg has been deposited, but eggs can be produced where there is no animal to lay them. Omne ovum e vivo will be no more true than Omne vivum ex ovo.

CHAPTER XXX.

WHILE the above exploits were being performed by Jamesy Doyle and the police, a sad scene indeed was being enacted at the bridge. Winny Cavana, whose bonds had been loosed, had rushed to where Emon lay with his head in his father's lap, while the two policemen, Cotter and Donovan, moved up with their prisoner. They not only handcuffed him, but had tied his legs together, and threw him on the side of the road, "to wait their convenience," while they rendered any assistance they could to the wounded

man.

The father had succeeded in stanching the blood, which at first had poured freely from the wound. With the assistance of one of the police, while the other was tying the prisoner, he had drawn his son up into a sitting posture and leaned him against the bank at the side of the road, and got his arm round him to sustain him. He was not shot dead; but was evidently very badly wounded. He was now, however, recovering strength and consciousness, as the blood ceased to flow.

"Open your eyes, Emon dear, if you are not dead, and look at your own Winny," she said; "your mad Winny Cavana, who brought you here to be murdered! Open your eyes, Emon, if you are not dead! I don't ask you to speak."

Emon not only opened his eyes, but turned his face and looked upon her. Oh, the ghastly smile he tried to hide! "Don't speak, Emon; but tell me with your eyes that you are not dying. No, no, Emon-Emon-a-knock! de

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mon as he is, he could not murder you. Heaven would not permit so much wickedness!"

Emon looked at her again. A faint but beautiful smile-beautiful now, for the color had returned to his cheeks beamed upon his lips as he shook his head.

"Yes, yes, he has murdered him," sobbed the distracted father; "and I pity you, Winny Cavana, as I hope you will pity his poor mother; to say nothing of myself."

"No, no, do not say so! He will not die, he shall not die!" And she pressed her burning lips to his marble forehead. It was smooth as alabaster, cold as ice.

"Win-ny Ca-va-na, good-by," he faintly breathed in her ear. "My days, my hours, my very moments are numbered. I feel death trembling in every vein, in every nerve. I couldcould-have-lived for you-Winny; but even-to die for you-is-a blessing, because-successful. One last request-Winny, my best beloved, is

all-I have to ask; spare me-a spot in Rathcash-chapel-yard, in the space allotted to-the-Cavanas. I feel some wonderful strength given me just now. It is a special mercy that I may speak with you before I go. But, Winny, my own precious, dearest love, do not deceive yourself. If I reach home to receive my mother's blessing before I die, it is the most-" and he leaned his head against his father's breast.

"No more delay!" cried Winny energetically, ergetically, "Time is too precious to be lost; bring the cart here, and let us take him home at once, and send for