"What nonsense!" grumbled Ned.

"It isn't; I feel so. It's just as if my body goes on while my feet keep sinking in the sand and won't keep up."

"I wish you wouldn't talk," said Ned.

"Why? Do you want to think?"

"No, of course I don't. I only want to keep on in this half-asleep way; it makes it a little better then."

Another halt at sundown, a fairly good meal, and a refreshing sleep, before the doctor roused all once more towards midnight for the tramp that was to last till about ten o'clock the next day. All was done this time in silence, save that Bourne tried to say hopefully--

"I should think we shall see the mountains quite clearly when day dawns."

But no one answered, for n.o.body believed they would. A feeling of despondency was making itself too plainly felt, and when broad daylight did at last come all that could be seen was sand and soda everywhere, not so much as a shrub or sc.r.a.p of gra.s.s, only scattered stones here and there, and the party shrank from looking in each other's wild and bloodshot eyes.

"Forward," said the doctor, at last. "We'll keep on till about two hours before noon, and then have a good meal and rest till the sun's low. We must be getting well on to our journey's end."

About this time the doctor edged up close to Griggs and entered into conversation with him in a low tone, "What do you think of it?" he said.

"Don't think at all, sir," was the reply.

"But we shall do it?"

"Must, sir."

"That's right," said the doctor, with a sigh of relief. "We must not think, but we must do it. We've got over the worst of it now, I feel sure."

The doctor was wrong, for there was an unexpected trouble ahead.

Towards the promised time for the halt there was what all took for a more hopeful sign: the plain was growing more stony and undulatory, while sage-brush peeped out in clumps here and there, to be gladly welcomed by the animals, which lost not an opportunity of cropping the bitter shoots.

The sun was getting hotter and hotter, and the doctor drew out his watch, to close it again with a snap which sounded curiously loud in the painful silence.

"Only another hour," he said, in a husky voice, "and then rest and breakfast."

He had hardly uttered the words when one of the mules, which had broken a little way from the line with outstretched muzzle, to nibble a few grey twigs, gave a leap which nearly dislodged its pack, and uttering a dismal squeal which was answered by two or three of its fellows, who turned their weary, straining eyes towards their companion, which now stood snorting and stamping angrily.

"What's the matter with the poor brute?" cried the doctor, who hurried towards the animal, closely followed by Griggs.

"Take care, sir--that," said the latter, in a whisper.

"That? What do you mean?"

"Bitten," said Griggs laconically, as he raised the double rifle that he had unslung, took a rapid aim, and fired the barrel loaded with small shot at what seemed to be an undulating line of grey sand.

The report sounded dull and dead, while as the smoke rose the undulating line of sand became a writhing tangle of something tying itself up into knots, untying itself, lashing the sand and dust up into a little cloud, and then as the dust rose the loathsome-looking length of a big snake became gradually clear to see, with the tail in the air announcing its owner's nature by keeping up a peculiar skirring sound something like the running down of a distant piece of clockwork.

"That's done for him," said Griggs, quietly reloading his piece.

"Almost as big a one as they make 'em."

The little party closed round the dying reptile, and then followed the doctor to where he stepped up to the mule, which kept on stamping and making efforts to curve round and bite at its near hind-leg, but could not reach it on account of the pack it bore.

Griggs slung his double rifle and seized the end of the pack-rope, casting loose the load and letting it slide to the ground, while the doctor cautiously approached to examine the place at which the mule now tore fiercely with its teeth.

"Better not, sir," said Griggs warningly.

"But I want to try and help the poor brute," said the doctor.

"Yes, sir; that's nice and humane," said Griggs; "but mules are not horses nor dogs. The poor brute is mad with agony, and you'll be kicked or bitten, to a dead certainty."

"I feel as if I must risk it," said the doctor. "I might inject ammonia, and save its life."

He approached closer, holding out one hand and speaking soothingly to the poor beast; but it turned upon him viciously and snapped at the extended hand like a dog, fortunately biting short, for the snap was sharper than the s.n.a.t.c.h back made by the doctor's hand.

"I told you so," said Griggs reproachfully. "Yes, we're going to be a mule short this morning."

For the effort seemed to be too much for the animal, which staggered, spread-out its legs far apart, uttered a wild squealing bray, fell over on one side, and lay kicking and plunging as if going at full gallop as it lay.

"You're right, Griggs," said the doctor. "But what strength there must be in that horrible poison! I should not have believed it would be so rapid and have such an effect upon an animal like that."

"It got a full dose of it close up where the skin's thinnest, I suppose; and it was a big rattler, and no mistake."

Just then the mule made an effort to rise to its feet, but sank back to its former position, and its kicking and plunging grew weaker and weaker, till it lay panting, with outstretched neck and heaving flanks, evidently dying fast.

"I might try and do something now," said the doctor thoughtfully, "if the poor beast were held."

"Too late," said Griggs quietly. "I don't understand much about snake poison, but I should say that's running all through the poor thing now."

But Chris's father would not give up. Hide-ropes were cast loose, while he hurried to the load which contained the little case of medicines and surgical appliances which was kept ready for emergencies, and then armed with bottle and syringe he superintended while nooses were placed round the poor animal's neck and four fetlocks, each being tightened and the rope held by some one. Chris and Ned were ordered to the fore-legs, Griggs took the neck rope, and Wilton and Bourne the hind-legs.

At a word from the doctor the ropes were drawn taut and the poor beast stretched out helplessly upon its back, while the doctor seated himself astride, sought for the tiny punctures made by the rattlesnake's poison-fangs, and found them where the skin was thinnest and most devoid of hair, the successful discovery being due to a tiny drop of yellowish gummy matter which had oozed out.

A caustic was applied to this as soon as the tiny wound had been freely lanced and set bleeding, and then with the proper instrument a strong application of ammonia was forced into one of the mule's larger veins, and all with the slightest of resistance being offered. Lastly, encouraged by the animal's quiescence, a strong stimulative ball was thrust beyond the tongue and seen to pa.s.s down the throat.

"I can do no more," said the doctor, "but I should not have been satisfied if I had not tried. Be careful now how you loosen the ropes."

There was no difficulty, for the patient lay as still as if it had been utterly stupefied by the poison, and seemed to all appearance stretched out dead.

Chris looked at Griggs, who loosened his noose last, and the man shook his head.

"Could it breathe while that rope was round its neck?" said the boy.

"Breathe? Yes, of course, my lad. The lariat did not press upon the wind-pipe. There's no strangling in the poor brute's case. It's poison's the matter there. I say, it has wakened us all up."

It was curious to note the effect to which Griggs had drawn attention.

Before the mule was stricken every one in the party had been giddy and ready to faint with heat and exhaustion, oppressed by a sense of despair and the dread that the end of the present journey would never be seen; but as soon as a demand was made upon their energies, all the other troubles seemed to be forgotten on the instant, and they worked together heartily and with wonderful spirit, till they all stood watching the motionless mule.

Bourne was the first to draw attention to the state of affairs, as he began wiping away the perspiration that streamed down his face.