When the British Secret Intelligence Service discovered that semen made a good invisible ink, Sir George Mansfield Smith-Cumming noted of his agents that "Every man (is) his own stylo".
Cand Serviciile Secrete de Inteligenta Britanica (British Secret Intelligence Service-SSB) a descoperit ca sperma poate fi o cerneala invizibila excelenta, Sir George Mansfield Smith-Cumming afirmase despre agentii sai ca "Fiecare barbat isi cara propriul stilou".