"Physiologizers!" Lucifer exclaimed, contemptuously.
"Let's keep our windows clean," Nina murmured.
He stared at her in surprise.
"My father used to say that," she explained. "He told us to keep our windows clean—so truth can look in and out."
Lucifer turned back the manuscript. He felt somehow chastened.
After several paragraphs of further discussion on the hereditary aspects of the various senses, even including the inheritance through a dominant gene of the ability to taste, the manuscript went into a long analysis of the family trees of Arturo Toscanini, Kirsten Flagstad and the 19th century mystic, Daniel Dunglas Home.
"Please note," the manuscript emphasized, "that in all three family trees a favorable heredity and a favorable environment were perfectly blended."
Nina gasped excitedly.
"Oh, Lucifer—if this project can bring the right parents together...."
"Human beings are not white mice!" Lucifer snapped!