I think it refers to the use of the 'Mouth' - if you suspected someone was an enemy of the state, you could write a note, drop it in the Mouth and the Council of Ten would deal with it. My Italian's rusty and Latin almost non-existent, but I believe "Denontie secrete" means "secret accusations".
穀歌上一個回答----這也是當年“穀歌”在裏海國被踢出去的原因,什麽都能查到,^_^。再謝古紙兄的文化滲透,問好。