Joseph Johnson, mistaking for emotion the queer little sounds which Warner did not entirely succeed in smothering with his handkerchief, sniffed and blinked his small eyes sympathetically, murmuring "_de-mort-nil-ni-b.u.m_."

When Warner had regained his self-control he asked the black man what he wanted.

"Sir, I am credibly informed that you are a distinguished member of a profession which has my humble but unqualified admiration and regard for what can be n.o.bler than the unselfish alleviation in others of the ills to which this weak flesh of ours is heir need I say the medical profession?"

"What then?"

"I suffer your honour from a slight but painful derangement of the vocal chords which hinders my fluency of enunciation and so disturbs my mental process as to detract from the strength of my disputations and dissertations."

"You mean you have a sore throat?"

"Sir, you grasp my meaning."

"You want some medicine for it?"

"Sir, if I might so far encroach upon your generosity...."

Warner rose hastily and walked to his goods piled up on the bank awaiting transportation, leaving Johnson to rumble on and on.

Here, then, was another patient. He must be careful. The man might know something and question his treatment. That would be most awkward.

"Corrosive sublimate? Wounds, the orderly had said, and had warned him about burning out the bottom of the pot used when mixing the stuff.

Better look through the rest before deciding.

"Pills? Might do the objectionable fellow some general good.

"Iodine? Yes, that's the stuff for him. Iodine for housemaid's knee or sore throat. Well, the man said he had a sore throat and he should know, so iodine let it be. Where's the brush?"

Warner opened the bottle. The cork was a little soft and inclined to crumble. He dipped the tip of the large camel's hair brush into the dark brown liquid and called Joseph Johnson to him.

"I am going to paint your throat. It also wants a thorough rest, so you must not talk more than is absolutely necessary."

"Thank you, sir."

"Now open."

The black man's mouth was immense. Warner had never seen such a cavern, nor, for that matter, had he ever seen such a perfect, strong, clean set of teeth. He gave little dabs here and there, this side and that, and then withdrew the brush.

"That's enough for this morning. Come again at sunset, and remember, don't talk."

This admonition he repeated in self-defence. He rather dreaded the man's brook of words.

His patient bent forward slightly, put on his sun helmet and walked away, his eyes watering a little.

The man was most obedient. Punctually at sunset he again appeared. He smiled pleasantly at Warner, but did not announce himself with any long-winded speech.

Warner looked at the throat and remarked that he thought it was better, that one or two applications would set it right. He then painted as before.

This time Johnson coughed and large tears rolled slowly down his cheeks.

Then it occurred to Warner that he himself, when a child, had had his throat painted, more than once. He recollected that the operation was not a pleasant one. He had coughed a great deal, and his eyes had watered very much. Clearly he was underdoing it. No matter, he would put that right to-morrow.

Warner was pleasantly surprised when, in the morning, the local natives came to tell him that they were about to cross the river with the last of his goods, after which they would take him if he was ready to go. He had expected the job to take at least another day.

He kept back the bottle of iodine and the camel's hair brush, and sat down on a camp stool to wait for Johnson.

In about a quarter of an hour the patient arrived.

"How are you this morning?" asked Warner pleasantly.

"Much better, I thank you, sir."

"Let's have a look. Capital, capital. Now don't move, I'll just touch it up."

Warner, remembering his overnight decision, plunged the brush deeply into the bottle and withdrew it fully charged and dripping.

He began to dab the throat here and there as before. A gurgling sound came from Joseph Johnson's mouth. Warner recognised the warning. He knew his time was distinctly limited. He felt that, if he did not hurry, much of the enormous cavern would remain unpainted. With a rapid movement, like one stirring porridge to save it from burning, he finished the job and stepped back.

Joseph Johnson seemed to explode. Tears forced their way through his tightly closed eyelids. A roar boomed from the painted throat. The patient's condition quite alarmed the doctor. Surely the fool wasn't going to die?

Looking round for inspiration, Warner saw that the native canoe had returned to ferry him across the river. He didn't actually run away, but quickly corking his bottle of iodine he walked briskly to the river bank, entered the canoe and told the crew to paddle to the other side.

He heaved a sigh of relief when he stepped ash.o.r.e. He looked back, but could see no sign of Joseph Johnson.

Some weeks later his troubled conscience was set at rest by the following letter:

"Bulawayo, "21/4/19.

"Honoured Sir,

"The enablement was not vouchsafed to me to indicate to Your Excellency the prodigious potentiality of the prophylactic applied with such consummate and conscientious technicality to my unostentatious tenement of clay. For full three weeks the taciturnity prescribed was obediently observed without difficulty or mutinousness of feeling. After which, rising from the slough of my despond, I found my multiloquence had returned fourfold, my linguacious allocution and discursive conversationalism prominently augmented. I then felt that my mission was not to the unenlightened ignoramusses of this neighbourhood but to the encyclopedical omnicients of the south. I have therefore returned to Bulawayo. Now here...."

As there were four closely written pages of this kind of thing, Warner turned to the last of them, which ended:

"Sir, I have the honour to be

"Your Honourable Excellency's most grateful, most humble, most obedient and unforgetful servant,

"JOSEPH JOHNSON."

CORROSIVE SUBLIMATE.

Late one afternoon some natives carried an old man, wrapped in a blanket, into Warner's camp and laid him down on the ground before the tent. Warner came out.

"What is this?" he asked.