Helena Maitland knows about it.

She lives next door, and saw the doctor's car at the Newtons' gate this morning." "I told you Joyce looked queer yesterday!" said Bessie Kirk.
"Suppose we all catch it!" shuddered Freda Long.
"Don't! It's too horrible!" There was a feeling of utter consternation among the girls as the bad news was discussed.

They wondered what was going to happen.
"Miss Bishop is telephoning to the Medical Officer of Health," volunteered Olave Parry, who had been downstairs to seek fresh information.
Just then Miss Huntley came into the room, though it was not yet nine o'clock.

She went at once to her desk and took the call over.
"What's going to happen about Joyce ?" one or two of the girls ventured to ask her.
"I don't know yet.

I expect we shall all be put into quarantine.