"Since balloons could not be flown back into Paris due to their erratic and uncontrollable flight patterns, the only means of getting information... was the carrier pigeon. Pigeons had been used to convey messages since antiquity, and a pigeon post... operated as late as 1850 by Paul Julius Reuter... proved... swifter than the railway in carrying stock prices between Brussels and . The carrier pigeons used in the Siege of Paris were able to carry much more information thanks to... microphotography invented by . In 1859 Dragon had received a patent for microfilm, and over the next decade he produced... photographs shrunk to fit inside jewels, signet rings [etc.]... He also developed... a profitable sideline in pornography... enjoyed with the aid of a special magnifying viewer. During the siege, Dagron turned.. to more patriotic endeavors. ...photographing government dispatches, shrinking them.., printing them on lightweight membranes.., and fitting as many as 40,000... into a canister strapped to the legs of a single carrier pigeon. The pigeons... encountering on their return to Paris... falcons specially trained by the Prussians. ...[T]he pigeons also carried personal communications."