I had expected to feel afraid or repulsed, but I found I was looking at him with a detached kind of pity. He was dying, clearly. He appeared to be at a distance from us already, as if death had moved in and taken possession before life was extinguished.

I watched my father bend over the bed and take the old man’s hand tenderly from under the bedclothes to feel his pulse. He spoke a few soft words. ‘Easy now,’ I heard him say. His daughter stood at the end of the bed with her arms folded across her large breasts.

Daddy turned to her. ‘There’s nothing more I can do, I’m afraid. You’re doing the best that can be done.’ The woman sighed and nodded stolidly and kept thanking Daddy before we left.

As we approached the next house, two children who had been waiting on the front step came running at the sight of the doctor, cheeping like young birds: ‘It’s the babby – he’s took real bad!’

They were both girls, both dressed in very worn gingham frocks, too big for the elder girl and too skimpy for the younger.

‘Our mom’s worried it’s the diphtheria or she’d have brought him to you.’

I stepped into the house with Daddy. The room was spotlessly clean, though with very little in the way of furniture. There was the black iron range, a table and two wooden chairs.

The young mother was pacing the cold bricks with bare feet, the baby in her arms. His eyes were half open and he was breathing in quick, panting breaths.

Daddy gently opened the child’s mouth. In a voice that was low but urgent he said, ‘Kate – outside. Now.’

I watched from the doorway with the other girls, whose eyes moved enviously over my dress.

‘You were right Mrs Smith,’ Daddy told her. ‘It is diphtheria. Little Tom is very ill. We’ll need to get him to the fever hospital.’

He spoke further of the child needing a hole in his windpipe to help him breathe, and of arranging transport, a blue-windowed diphtheria van. When we left I had even more trouble keeping up with him. He strode down the street, lips pressed tightly together. I wondered once more whether I’d done something wrong.

In the end I asked timidly, ‘That baby was very ill, wasn’t it?’

‘We ought to be able to do something.’ The words burst out of him. ‘We ought to be able to prevent children from getting terrible diseases like that. It’s a scourge – it’s dreadful. I can’t bear to see it.’

I’d never seen this grief in him before. I felt like crying myself, and could only trot along silently beside him.

He looked down at my miserable face and suddenly smiled. ‘Hey now. Don’t you go worrying, Katie. It’s not your fault.’ He laid his hand on my shoulder for a moment. ‘Come on. We’ve one more call to make.’

I waited downstairs in a filthy room in one of the back-houses, facing out over a yard strung across with washing. The room was very dark and stuffy and on the table were the remains of what looked like several days’ worth of meals. The old oilcloth was soaked with spilled tea and the remains of some kind of stew. There were plates covered with congealed gravy, several jam jars with a crust of dried tea-leaves at the bottom and an old heel of bread. The floor was strewn with food remains and dirty clothes from which rose a rank, sweaty smell. And there was another terrible odour about the house which I couldn’t identify but which turned my stomach.