The company then, to my embarrassment, started to mumble my name over and over again. Almost all were saying it, except one who began to utter a small piercing noise resembling very well the cry of the peewit. I did not know what was expected of me in the way of words, so I said nothing but performed a little obeisance such as I used to perfect before a looking glass in my Whitehall days. And I followed Ambrose out and we walked in the rain to Margaret Fell.

We found Hannah and Eleanor here. The pallets had been rolled away and the night pails emptied and bowls of cold water had been brought, in which the women of Margaret Fell were washing their faces and hands with a blackish soap. They were about thirty-five in number and of all ages, the youngest being no more than twenty or twenty-five.

"Tell me," I whispered to Ambrose, as I was shown the carding combs and spinning wheels with which the women worked to produce a grey lumpy yarn that was made into mops, "how have such young people been brought to madness?"

"By a hundred ways, Robert," he replied. "Madness is brother and sister to misfortune, not to age. Poverty is a prime cause. Abandonment another. We have one here, Katharine, who was deserted by her young husband in the middle of the night and now she will not, cannot, sleep and all her madness is from the exhaustion of her brain and body."

"Which one is Katharine?"

"There, washing her neck. With her clothes very torn. For this is what she does in the night: sits and tears to rags whatever we dress her in."

I looked towards this person. I saw a tall but thin young woman with black hair straggling to her waist and black eyes that reminded me of Farthingale's, except that they were larger and sadder and the skin under them bruised by her sleeplessness.

"There are cures for such an affliction," I said, remembering that at Cambridge Pearce used to chew mallow root and endive to still his moist brain into repose.

"Yes," said Ambrose, "and we try them for Katharine and sometimes she will sleep an hour or more, but a shortness of breath wakes her. She feels herself to be suffocating and speaks to us of weights on her head, pushing her down."

I was touched by the condition of this woman and, as Ambrose once again made the request that the inmates of Margaret Fell ponder my name and say it to themselves, I wondered at the power this word "sleep" has assumed in my mind. Days were coming, I was certain, when I would have to open my case of silver-handled surgical instruments and hold in my unpractised hand the scalpel with the words "Do Not Sleep" upon it. In allowing myself to become Robert I had surely ended what the King called my "dreaming time", and in my state of wakefulness much of what I longed to forget or ignore would now be grossly visible to me once more. And what must I come across on my very first day but a woman who slept not at all and whose wakeful stare – a perpetual, uncourted vigil over all the hours of light and dusk, darkness and dawn – had brought her to madness? Can there be, I thought bitterly, any more terrible exhortation on earth than that which the King had given me? When he gave the words to the engraver, what degree of suffering did he have in mind for me?

As if to answer this question, I soon found myself with Ambrose inside the third habitation of the Whittlesea Hospital, the place they call William Harvey.

"I have already suggested to you that anyone entering here for the first time feels as if he has stumbled into hell. Except that it is not fiery. It is chill and dark and foetid, having only one small barred window in it and no rushlights or candles at all, for fear the inmates might wound themselves with an open flame or set on fire the straw pallets.

The people in William Harvey are kept chained up and harnessed to bolts in the wall and truly the existence of the King's lions in the Tower is more free than theirs. But these are people descended so far into madness that they would, if not clamped into iron, commit obscenity or murder upon each other or mutilate their own bodies which, from the great restlessness of their limbs, appear as if truly possessed by some devilish power.

There are twenty-one of them: sixteen men and five women. All have scars in their foreheads where blood has been let, this and the trepanning of the skull (not practised by the Quakers) being the most fearsome of the supposed cures for insanity. I walked with Ambrose the length of the barn and I looked into their eyes one by one and I remembered that it was of such crazed and suffering people that Pearce had once said "they are the only innocent of the age, which itself is a lunatic age, because they are indifferent to glory". And a familiar shiver of irritation with Pearce went through me, it being the case with him that he believes too excessively in the truth of his own pronouncements, some of which are most wise and profound, but yet others of which are transparently foolish.

"Do you believe," I asked Ambrose (who had made no attempt to persuade the inhabitants of William Harvey to learn my name), "that Whittlesea can cure these people?"

He put his large hand on my shoulder.

"I believe, Robert," he said, "that if Jesus wishes it, they will be cured. Already, we have seen cures in William Harvey." And he then proceeded to tell me the story of the women who had voided "two great worms", the very same tale Pearce had told me on the way to Bidnold churchyard to dig for saltpetre, the tale with which he had sought to convince me of the folly of hope. It had affected me at the time, but now that I was standing in the very place where it had happened, the story produced in me a feeling of revulsion so profound that some bile came into my throat and I believe I would have vomited had not Ambrose spied my distress and opened the door of William Harvey so that I could escape into the light of the damp morning.

That night (and all the month of nights since the first one), we, the Keepers of Whittlesea, ate a supper of fish, vegetables and bread cooked by Daniel in the kitchen and we spoke of our day which, to me, had been worse than any day I had spent dissecting cadavers at Padua or tending the poor sick of St Thomas's.

In the middle of this supper, I heard outside a wounding, familiar noise: it was the whinny of Danseuse. And of course I was once again tempted, then and there as I tried to swallow some greasy mackerel, to saddle my mare and ride away. But I did not. And Pearce had his eye upon me and seemed to know my thoughts. "Robert," he said kindly, "when you join us in our Meeting in our parlour, try to cast from your mind all old longings, so that you may be filled with the words of Christ and, through Him, speak to us."

"Yes, John," I said. "I will try."

Before the Meetings, the six Keepers (and now I, the seventh) take up lamps and go round the three madhouses being "tender". Our behaviour each night reminds me of King Harry's before Agincourt, except that we are not exhorting the lunatics to fight courageously on the morrow, but to still their souls in preparation for sleep. We inform them that Christ is in them ("as surely," I heard Pearce say, "as if He were the very blood that moves in a circle out from your heart and to it again") and is therefore keeping all safe during the night.

The straw beds are then laid out and the occupants of George Fox and Margaret Fell lie down upon them and cover their bodies, each with his grey blanket. And then we say a prayer over them and bid them goodnight and take the lamps away and they are left in their rows in the darkness. But the men and women of William Harvey are seldom quietened by our "tenderness", some not recognising night from day and seeming to have no knowledge of what sleep is until it overtakes them. And from my room, which is an exceedingly small place somewhat resembling my linen cupboard at Bidnold, I can often hear crying and howling coming from WH.