The incident just related was, as the reader has guessed before this, the diabolical work of Mynheer Isaac Boxtel.

It will be remembered that, with the help of his telescope, not even the least detail of the private meeting between Cornelius de Witt and Van Baerle had escaped him. He had, indeed, heard nothing, but he had seen everything, and had rightly concluded that the papers intrusted by the Warden to the Doctor must have been of great importance, as he saw Van Baerle so carefully secreting the parcel in the drawer where he used to keep his most precious bulbs.

The upshot of all this was that when Boxtel, who watched the course of political events much more attentively than his neighbour Cornelius was used to do, heard the news of the brothers De Witt being arrested on a charge of high treason against the States, he thought within his heart that very likely he needed only to say one word, and the godson would be arrested as well as the godfather.

Yet, full of happiness as was Boxtel's heart at the chance, he at first shrank with horror from the idea of informing against a man whom this information might lead to the scaffold.

But there is this terrible thing in evil thoughts, that evil minds soon grow familiar with them.

Besides this, Mynheer Isaac Boxtel encouraged himself with the following sophism: -

"Cornelius de Witt is a bad citizen, as he is charged with high treason, and arrested.

"I, on the contrary, am a good citizen, as I am not charged with anything in the world, as I am as free as the air of heaven."

"If, therefore, Cornelius de Witt is a bad citizen, - of which there can be no doubt, as he is charged with high treason, and arrested, - his accomplice, Cornelius van Baerle, is no less a bad citizen than himself.

"And, as I am a good citizen, and as it is the duty of every good citizen to inform against the bad ones, it is my duty to inform against Cornelius van Baerle."

Specious as this mode of reasoning might sound, it would not perhaps have taken so complete a hold of Boxtel, nor would he perhaps have yielded to the mere desire of vengeance which was gnawing at his heart, had not the demon of envy been joined with that of cupidity.

Boxtel was quite aware of the progress which Van Baerle had made towards producing the grand black tulip.

Dr. Cornelius, notwithstanding all his modesty, had not been able to hide from his most intimate friends that he was all but certain to win, in the year of grace 1673, the prize of a hundred thousand guilders offered by the Horticultural Society of Haarlem.

It was just this certainty of Cornelius van Baerle that caused the fever which raged in the heart of Isaac Boxtel.

If Cornelius should be arrested there would necessarily be a great upset in his house, and during the night after his arrest no one would think of keeping watch over the tulips in his garden.

Now in that night Boxtel would climb over the wall and, as he knew the position of the bulb which was to produce the grand black tulip, he would filch it; and instead of flowering for Cornelius, it would flower for him, Isaac; he also, instead of Van Baerle, would have the prize of a hundred thousand guilders, not to speak of the sublime honour of calling the new flower Tulipa nigra Boxtellensis, - a result which would satisfy not only his vengeance, but also his cupidity and his ambition.

Awake, he thought of nothing but the grand black tulip; asleep, he dreamed of it.

At last, on the 19th of August, about two o'clock in the afternoon, the temptation grew so strong, that Mynheer Isaac was no longer able to resist it.

Accordingly, he wrote an anonymous information, the minute exactness of which made up for its want of authenticity, and posted his letter.

Never did a venomous paper, slipped into the jaws of the bronze lions at Venice, produce a more prompt and terrible effect.

On the same evening the letter reached the principal magistrate, who without a moment's delay convoked his colleagues early for the next morning. On the following morning, therefore, they assembled, and decided on Van Baerle's arrest, placing the order for its execution in the hands of Master van Spennen, who, as we have seen, performed his duty like a true Hollander, and who arrested the Doctor at the very hour when the Orange party at the Hague were roasting the bleeding shreds of flesh torn from the corpses of Cornelius and John de Witt.

But, whether from a feeling of shame or from craven weakness, Isaac Boxtel did not venture that day to point his telescope either at the garden, or at the laboratory, or at the dry-room.

He knew too well what was about to happen in the house of the poor doctor to feel any desire to look into it. He did not even get up when his only servant - who envied the lot of the servants of Cornelius just as bitterly as Boxtel did that of their master - entered his bedroom. He said to the man, -

"I shall not get up to-day, I am ill."

About nine o'clock he heard a great noise in the street which made him tremble, at this moment he was paler than a real invalid, and shook more violently than a man in the height of fever.

His servant entered the room; Boxtel hid himself under the counterpane.

"Oh, sir!" cried the servant, not without some inkling that, whilst deploring the mishap which had befallen Van Baerle, he was announcing agreeable news to his master, - "oh, sir! you do not know, then, what is happening at this moment?"

"How can I know it?" answered Boxtel, with an almost unintelligible voice.

"Well, Mynheer Boxtel, at this moment your neighbour Cornelius van Baerle is arrested for high treason."

"Nonsense!" Boxtel muttered, with a faltering voice; "the thing is impossible."

"Faith, sir, at any rate that's what people say; and, besides, I have seen Judge van Spennen with the archers entering the house."

"Well, if you have seen it with your own eyes, that's a different case altogether."

"At all events," said the servant, "I shall go and inquire once more. Be you quiet, sir, I shall let you know all about it."

Boxtel contented himself with signifying his approval of the zeal of his servant by dumb show.

The man went out, and returned in half an hour.

"Oh, sir, all that I told you is indeed quite true."

"How so?"

"Mynheer van Baerle is arrested, and has been put into a carriage, and they are driving him to the Hague."

"To the Hague!"

"Yes, to the Hague, and if what people say is true, it won't do him much good."

"And what do they say?" Boxtel asked.

"Faith, sir, they say - but it is not quite sure - that by this hour the burghers must be murdering Mynheer Cornelius and Mynheer John de Witt."

"Oh," muttered, or rather growled Boxtel, closing his eyes from the dreadful picture which presented itself to his imagination.

"Why, to be sure," said the servant to himself, whilst leaving the room, "Mynheer Isaac Boxtel must be very sick not to have jumped from his bed on hearing such good news."

And, in reality, Isaac Boxtel was very sick, like a man who has murdered another.

But he had murdered his man with a double object; the first was attained, the second was still to be attained.

Night closed in. It was the night which Boxtel had looked forward to.

As soon as it was dark he got up.

He then climbed into his sycamore.

He had calculated correctly; no one thought of keeping watch over the garden; the house and the servants were all in the utmost confusion.

He heard the clock strike - ten, eleven, twelve.

At midnight, with a beating heart, trembling hands, and a livid countenance, he descended from the tree, took a ladder, leaned it against the wall, mounted it to the last step but one, and listened.

All was perfectly quiet, not a sound broke the silence of the night; one solitary light, that of the housekeeper, was burning in the house.

This silence and this darkness emboldened Boxtel; he got astride the wall, stopped for an instant, and, after having ascertained that there was nothing to fear, he put his ladder from his own garden into that of Cornelius, and descended.

Then, knowing to an inch where the bulbs which were to produce the black tulip were planted, he ran towards the spot, following, however, the gravelled walks in order not to be betrayed by his footprints, and, on arriving at the precise spot, he proceeded, with the eagerness of a tiger, to plunge his hand into the soft ground.

He found nothing, and thought he was mistaken.

In the meanwhile, the cold sweat stood on his brow.

He felt about close by it, - nothing.

He felt about on the right, and on the left, - nothing.

He felt about in front and at the back, - nothing.

He was nearly mad, when at last he satisfied himself that on that very morning the earth had been disturbed.

In fact, whilst Boxtel was lying in bed, Cornelius had gone down to his garden, had taken up the mother bulb, and, as we have seen, divided it into three.

Boxtel could not bring himself to leave the place. He dug up with his hands more than ten square feet of ground.

At last no doubt remained of his misfortune. Mad with rage, he returned to his ladder, mounted the wall, drew up the ladder, flung it into his own garden, and jumped after it.

All at once, a last ray of hope presented itself to his mind: the seedling bulbs might be in the dry-room; it was therefore only requisite to make his entry there as he had done into the garden.

There he would find them, and, moreover, it was not at all difficult, as the sashes of the dry-room might be raised like those of a greenhouse. Cornelius had opened them on that morning, and no one had thought of closing them again.

Everything, therefore, depended upon whether he could procure a ladder of sufficient length, - one of twenty-five feet instead of ten.

Boxtel had noticed in the street where he lived a house which was being repaired, and against which a very tall ladder was placed.

This ladder would do admirably, unless the workmen had taken it away.

He ran to the house: the ladder was there. Boxtel took it, carried it with great exertion to his garden, and with even greater difficulty raised it against the wall of Van Baerle's house, where it just reached to the window.

Boxtel put a lighted dark lantern into his pocket, mounted the ladder, and slipped into the dry-room.

On reaching this sanctuary of the florist he stopped, supporting himself against the table; his legs failed him, his heart beat as if it would choke him. Here it was even worse than in the garden; there Boxtel was only a trespasser, here he was a thief.

However, he took courage again: he had not gone so far to turn back with empty hands.

But in vain did he search the whole room, open and shut all the drawers, even that privileged one where the parcel which had been so fatal to Cornelius had been deposited; he found ticketed, as in a botanical garden, the "Jane," the "John de Witt," the hazel-nut, and the roasted-coffee coloured tulip; but of the black tulip, or rather the seedling bulbs within which it was still sleeping, not a trace was found.

And yet, on looking over the register of seeds and bulbs, which Van Baerle kept in duplicate, if possible even with greater exactitude and care than the first commercial houses of Amsterdam their ledgers, Boxtel read these lines: -

"To-day, 20th of August, 1672, I have taken up the mother bulb of the grand black tulip, which I have divided into three perfect suckers."

"Oh these bulbs, these bulbs!" howled Boxtel, turning over everything in the dry-room, "where could he have concealed them?"

Then, suddenly striking his forehead in his frenzy, he called out, "Oh wretch that I am! Oh thrice fool Boxtel! Would any one be separated from his bulbs? Would any one leave them at Dort, when one goes to the Hague? Could one live far from one's bulbs, when they enclose the grand black tulip? He had time to get hold of them, the scoundrel, he has them about him, he has taken them to the Hague!"

It was like a flash of lightning which showed to Boxtel the abyss of a uselessly committed crime.

Boxtel sank quite paralyzed on that very table, and on that very spot where, some hours before, the unfortunate Van Baerle had so leisurely, and with such intense delight, contemplated his darling bulbs.

"Well, then, after all," said the envious Boxtel, - raising his livid face from his hands in which it had been buried - "if he has them, he can keep them only as long as he lives, and - - "

The rest of this detestable thought was expressed by a hideous smile.

"The bulbs are at the Hague," he said, "therefore, I can no longer live at Dort: away, then, for them, to the Hague! to the Hague!"

And Boxtel, without taking any notice of the treasures about him, so entirely were his thoughts absorbed by another inestimable treasure, let himself out by the window, glided down the ladder, carried it back to the place whence he had taken it, and, like a beast of prey, returned growling to his house.