“Look at this, David,” he said. “Any idea what that might be?”

It was a flat metal plate about six inches by three, and perhaps three-quarters of an inch thick, and at one end of it was a round button.

“That’s for rheumatism,” he said. “People with rheumatism always tell the doctor they can’t move. Seized right up so they can’t budge. Now this thing here, Davey, is called a scarifier. Suppose a man has a bad back. Nothing helps him. Well, in the old days, they’d hold this thing here right tight up against where he was stiff, and then they’d press this button—”

Here he pressed the button, and from the surface of the metal plate leapt twelve tiny knife-points, perhaps an eighth of an inch long.

“Then he’d budge,” said Grandfather, and laughed.

His laugh was one I have never heard in anyone else; he did not blow laughter out, he sucked it in, with a noise that sounded like snuk-snuk, snuk-snuk, snuk.

He put the scarifier away and took out a cigar and hooked the spittoon toward him with his foot, and I knew I was dismissed, having had my first practical lesson in medicine.

What he taught Netty was the craft of dealing with constipation. He had been trained in an era when this was a great and widespread evil, and in rural districts it was, as he himself said with unconscious humour, a corker. Farm people understandably dreaded their draughty privies in winter and cultivated their powers of retention to a point where, in my grandfather’s opinion, they were inviting every human ill. During his more active days as a doctor he had warred against constipation, and he kept up the campaign at home. Was I delicate? Obviously I was full of poisons, and he knew what to do. On Friday nights I was given cascara sagrada, which rounded up the poisons as I slept, and on Saturday morning, before breakfast, I was given a glass of Epsom salts to drive them forth. On Sunday morning, therefore, I was ready for church as pure as the man from whom Paul drove forth the evil spirits. But I suppose I became habituated to these terrible weekly aids, and nothing happened in between. Was Doc Staunton beaten? He was not. I was a candidate for Dr Tyrrell’s Domestic Internal Bath.

This nasty device had been invented by some field-marshal in the war against auto-intoxication, and it was supposed to bring all the healing miracle of Spa or Aix-les-Bains to its possessor. It was a rubber bag of a disagreeable gray colour, on the upper side of which was fixed a hollow spike of some hard, black composition. It was filled with warm water until it was fat and ugly; I was impaled on the spike, which had been greased with Vaseline; a control stopcock was turned, and my bodily weight was supposed to force the water up inside me to seek out the offending substances. I was not quite heavy enough, so Netty helped by pushing downward on my shoulders. As I was dismayingly invaded below, her breath, like scorching beef, blew in my face. Oh, Calvary!