'Can you not imagine a rival overhearing, perhaps, the appointment in the conservatory? If he is a good mimic or a ventriloquist, say, it would be easy to utter a few words behind the palms, impersonating two people; then, as his victim approaches, he glides behind some other leafy screen, to appear before you, perhaps, a little later, smiling and secretly triumphant.'

'I see!' she said, with sudden energy. 'Tell me what must—what ought I to do?'

'Will you take my advice, with a strong reason behind it?'

'Yes,' promptly.

'Then, say nothing, do nothing, for the present. Believe me, it will be best in the end, and an especial favour to me. I will explain more fully at another time.' I got up and stood before her, watch in hand. 'We are due at the hospital. Do you agree?'

'To wait?' She arose quickly. 'Will it really be a favour to you?'

'It will be a great favour. It will disarrange my most cherished plans for unmasking a villain if you make a sign too soon.'

'Then I will hold my peace; I will help you, even—can I?'

'Will you?'

'I will.' She put out her hand.