"No maid like dormouse on me wait,
Nor leech-like host be here my fate."
But, on the supposition that guest is the proper meaning, "hirudo" might be taken in the sense of a greedy guest, although this would not be complimentary to the older hospitality. And even in the sense of gossiping, "hirudo" would not be so inappropriate an imitation of the "recitator acerbus" at the conclusion of the Ars Poetica:
"Nec missura cutem nisi plena cruoris hirudo."
E. L. B.
Ruthin.
PHOTOGRAPHIC NOTES AND QUERIES.
Photographic Gun-Cotton.—The "doctors differ" not a little in their prescriptions for preparing the best gun-cotton for photographic use. How shall the photographer decide between them?
Dr. Diamond ("N. & Q.," Vol. vi., p. 277.) says (I quote briefly), "Pour upon 100 grains of cotton an ounce and a half of nitric acid, previously mixed with one ounce of strong sulphuric acid. Knead it with glass rods during five minutes," &c.