it quite distinctly, with its wings flattened out, upon the old stone wall that runs along the west edge of the park, but going up to it he found it was only two lumps of grey and yellow lichen. "This," said Hapley, "is the reverse of mimicry. Instead of a butterfly looking like a stone, here is a stone looking like a butterfly!" Once something hovered and fluttered round his head, but by an effort of will he drove that impression out of his mind again.
In the afternoon Hapley called upon the Vicar, and argued with him upon theological questions. They sat in the little arbour covered with briar, and smoked as they wrangled. "Look at that moth!" said Hapley, suddenly, pointing to the edge of the wooden table.
"Where?" said the Vicar.
"You don't see a moth on the edge of the table there?" said Hapley.
"Certainly not," said the Vicar.
Hapley was thunderstruck. He gasped. The Vicar was staring at him. Clearly the man saw nothing. "The eye of faith is no better than the eye of science," said Hapley awkwardly.
"I don't see your point," said the Vicar, thinking it was part of the argument.
That night Hapley found the moth crawling over his counterpane. He sat on the edge of the bed in his shirt sleeves and reasoned with himself. Was it pure hallucination? He knew he was slipping, and he battled for his sanity with the same silent energy he had formerly displayed against Pawkins. So persistent is mental habit, that he felt as if it were still a struggle with Pawkins. He was well versed in psychology. He knew that such visual illusions do come as a result of mental strain. But the
