“Go further back.  Take typhoid fever with its delirium, influenza with its suicide mania.  All due to toxins—­poisons.  Chemistry—­ chemistry—­all of them chemistry.”

Craig had begun carefully so as to win their attention.  He had it as he went on:  “Do we not brew within ourselves poisons which enter the circulation and pervade the system?  A sudden emotion upsets the chemistry of the body.  Or poisonous food.  Or a drug.  It affects many things.  But we could never have had this chemical theory unless we had had physiological chemistry—­and some carry it so far as to say that the brain secretes thought, just as the liver secretes bile, that thoughts are the results of molecular changes.”

“You are, then, a materialist of the most pronounced type,” asserted Dr. Crafts.

Kennedy had been reaching over to a table, toying with the phonograph.  As Crafts spoke he moved a key, and I suspected that it was in order to catch the words.

“Not entirely,” he said.  “No more than some eugenists.”

“In our field,” put in Maude Schofield, “I might express the thought this way—­the sociologist has had his day; now it is the biologist, the eugenist.”

“That expresses it,” commented Kennedy, still tinkering with the record.  “Yet it does not mean that because we have new ideas, they abolish the old.  Often they only explain, amplify, supplement.  For instance,” he said, looking up at Edith Atherton, “take heredity.  Our knowledge seems new, but is it?  Marriages have always been dictated by a sort of eugenics.  Society is founded on that.”

“Precisely,” she answered.  “The best families have always married into the best families.  These modern notions simply recognize what the best people have always thought—­except that it seems to me,” she added with a sarcastic flourish, “people of no ancestry are trying to force themselves in among their betters.”

“Very true, Edith,” drawled Burroughs, “but we did not have to be brought here by Quincy to learn that.”

Quincy Atherton had risen during the discussion and had approached Kennedy.  Craig continued to finger the phonograph abstractedly, as he looked up.

“About this—­this insanity theory,” he whispered eagerly.  “You think that the suspicions I had have been justified?”

I had been watching Kennedy’s hand.  As soon as Atherton had started to speak, I saw that Craig, as before, had moved the key, evidently registering what he said, as he had in the case of the others during the discussion.

“One moment, Atherton,” he whispered in reply, “I’m coming to that.  Now,” he resumed aloud, “there is a disease, or a number of diseases, to which my remarks about insanity a while ago might apply very well.  They have been known for some time to arise from various affections of the thyroid glands in the neck.  These glands, strange to say, if acted on in certain ways can cause degenerations of mind and body, which are well known, but in spite of much study are still very little understood.  For example, there is a definite interrelation between them and sex—­especially in woman.”