“Evil—­but for whom?” Old Galen poured the powder he had scraped into a dish and blinked at him.  “Affiliations in the realm of substance are confined to like ingredients.  That law is universal.  Like seeks like, begetting its own like.  As for instance, sickness flows in channels of unwholesomeness, like water seeping through a marsh.  Evil?  What is evil but the likeness of a deed—­its echo—­its result—­its aftermath?  You see this powder?  Marcia has ordered me to poison Commodus!  What kind of aftermath should that deed have?”

Sextus stared at him astonished.  Galen went on mixing.

“Colorless it must be—­flavorless—­without smell—­indetectible.  These saviors of Rome prepare too much to save themselves!  And I take trouble to save myself.  Why?”

He stopped and blinked again at Sextus, waiting for an answer.

“You are worth preserving, Galen.”

“I dispute that.  I am sentimental, which is idiocy in a man of my age.  But I will not kill him who is superior to any man in Rome.”

“Idiocy?  You?  And you admire that monster?”

“As a monster, yes.  He is at least wholehearted.  As a monster he lacks neither strength of will nor sinew nor good looks; he is magnificent; he has the fear, the frenzy and the resolution of a splendid animal.  We have only cowardice, the unenthusiasm and the indecision of base men.  If we had the virtue of Commodus, no Commodus could ever have ruled Rome for half a day.  But I am senile.  I am sentimental.  Rather than betray Marcia—­and Pertinax—­who would betray me for their own sakes; rather than submit my own old carcass to the slave whom Marcia would send to kill me, I am doing what you see.”

“Poison for Commodus?”

“No.”

“Not for yourself, Galen?”

“No.”

“For whom then?”

“For Pertinax.”

Sextus seized the plate on which the several ingredients were being mixed.

“Put that down,” said Galen.  “I will poison part of him—­the mean part.”

“Speak in plain words, Galen!”

“I will slay his indecision.  He and Marcia propose; that I shall kill their monster.  I shall mix a draught for Marcia to take to him—­in case this, and in case that, and perhaps.  In plain words, Commodus has sent for Livius and none knows how much Livius has told.  Their monster writes and scratches out and rewrites long proscription lists, and Marcia trembles for her Christians.  For herself she does not tremble.  She has ten times Pertinax’ ability to rule.  If Marcia were a man she should be emperor!  Our Pertinax is hesitating between inertia and doubt and dread of Cornificia’s ambition for him; between admiration of his own wife and contempt for her; between the subtleties of auguries and common sense; between trust and mistrust of us all, including Marcia and you and me; between the easy dignity of being governor of Rome and the uneasy palace—­slavery of being Caesar; between doubt of his own ability to rule and the will to restore the republic.”