Papanicolaou stain

I put my hands behind my head, lay back and looked at a water stain on the ceiling.

Beginners must be warned against mistaking the edges of cells, or particles which have retained the red stain, for bacilli.

There are a number of bacilli, called acid-fast bacilli, which stain in the same way as the tubercle bacillus.

Louis pressed his father's hand to his lips; that hand which was hardly washed from the stain of Wharton's blood!

There was still visible on it the stain where he had wiped his hand, and this stain seemed certainly blood.

He did not think of the matter again till just as he was getting into bed, when he noticed a red stain upon his handkerchief.