“Why, everything,” said Calhoun mildly.  “It seems that Darians can pass for Wealdians whenever they please.  That they are passing for Wealdians.  That they’ve been mixing with your men, wearing sag-suits exactly like the one you’re wearing now.  They’ve been going aboard your ships in the confusion of returning looters.  There’s not a ship now aloft, which has been aground today, which hasn’t from one to fifteen Darians—­no longer blueskins—­on board.”

The admiral roared.  Then his face turned gray.

“You can’t take your fleet back to Weald,” said Calhoun gently, “if you believe its crews have been exposed to carriers of the Dara plague.  You wouldn’t be allowed to land, anyhow.”

The admiral said through stiff lips, “I’ll blast—­”

“No,” said Calhoun, again gently.  “When you ordered all ships alerted for action, the Darians on each ship released panic gas.  They only needed tiny, pocket-sized containers of the gas for the job.  They had them.  They only needed to use air tanks from their sag-suits to protect themselves against the gas.  They kept them handy.

“On nearly all your ships aloft your crews are crazy from panic gas.  They’ll stay that way until the air is changed.  Darians have barricaded themselves in the control rooms of most if not all your ships.  You haven’t got a fleet.  The few ships who will obey your orders—­if they drop one bomb, our fleet off Weald will drop fifty.

“I don’t think you’d better order offensive action.  Instead, I think you’d better have your fleet medical officers come and learn some of the facts of life.  There’s no need for war between Dara and Weald, but if you insist....”

The admiral made a choking noise.  He could have ordered Calhoun killed, but there was a certain appalling fact.  The men aground from the fleet were breathing Wealdian air from tanks.  It would last so long only.  If they were taken on board the still obedient ships overhead, Darians would unquestionably be mixed with them.  There was no way to take off the parties now aground without exposing them to contact with Darians, on the ground or in the ships.  There was no way to sort out the Darians.

“I—­I will give the orders,” said the admiral thickly.  “I do not know what you devils plan, but—­I do not know how to stop you.”

“All that’s necessary,” said Calhoun warmly, “is an open mind.  There’s a misunderstanding to be cleared up, and some principles of planetary health practises to be explained, and a certain amount of prejudice that has to be thrown away.  But nobody need die of changing their minds.  The Interstellar Medical Service has proved that over and over!”

Murgatroyd, perched on his shoulder, felt that it was time to take part in the conversation.  He said, “Chee-chee!”

“Yes,” agreed Calhoun.  “We do want to get the job done.  We’re behind schedule now.”

* * * * *