“She will tell me all,” he thought, and with a bound he was in the street.  He reached it just in time to see the blue brougham turn the corner of the Rue St. Lazare.

“Heavens!” he murmured.  “I shall lose sight of her, and yet she can tell me the truth.”

He was in one of those states of nervous excitement which engender prodigies.  He ran to the end of the Rue St. Lazare as rapidly as if he had been a young man of twenty.

Joy!  He saw the blue brougham a short distance from him in the Rue du Havre, stopped in the midst of a block of carriages.

“I have her,” said he to himself.  He looked all about him, but there was not an empty cab to be seen.  Gladly would he have cried, like Richard the III., “My kingdom for a cab!”

The brougham got out of the entanglement, and started off rapidly towards the Rue Tronchet.  The old fellow followed.

He kept his ground.  The brougham gained but little upon him.

While running in the middle of the street, at the same time looking out for a cab, he kept saying to himself:  “Hurry on, old fellow, hurry on.  When one has no brains, one must use one’s legs.  Why didn’t you think to get this woman’s address from Clergeot?  You must hurry yourself, my old friend, you must hurry yourself!  When one goes in for being a detective, one should be fit for the profession, and have the shanks of a deer.”

But he was losing ground, plainly losing ground.  He was only halfway down the Rue Tronchet, and quite tired out; he felt that his legs could not carry him a hundred steps farther, and the brougham had almost reached the Madeleine.

At last an open cab, going in the same direction as himself, passed by.  He made a sign, more despairing than any drowning man ever made.  The sign was seen.  He made a supreme effort, and with a bound jumped into the vehicle without touching the step.

“There,” he gasped, “that blue brougham, twenty francs!”

“All right!” replied the coachman, nodding.

And he covered his ill-conditioned horse with vigorous blows, muttering, “A jealous husband following his wife; that’s evident.  Gee up!”

As for old Tabaret, he was a long time recovering himself, his strength was almost exhausted.

For more than a minute, he could not catch his breath.  They were soon on the Boulevards.  He stood up in the cab leaning against the driver’s seat.

“I don’t see the brougham anywhere,” he said.

“Oh, I see it all right, sir.  But it is drawn by a splendid horse!”

“Yours ought to be a better one.  I said twenty francs; I’ll make it forty.”

The driver whipped up his horse most mercilessly, and growled, “It’s no use, I must catch her.  For twenty francs, I would have let her escape; for I love the girls, and am on their side.  But, fancy!  Forty francs!  I wonder how such an ugly man can be so jealous.”

Old Tabaret tried in every way to occupy his mind with other matters.  He did not wish to reflect before seeing the woman, speaking with her, and carefully questioning her.