The discredit under which this traveller fell is the more surprising because the same custom had already been noted by Sir John Mandeville, who, in speaking of Syria and adjacent countries, says: "In that contree, and other contrees beyond, thei have custom, whan thei schulle usen warre, and when men holden sege abouten Cytee or Castelle, and thei withinen dur not senden messagers with lettres frō Lord to Lord for to ask Sokour, thei maken here Lettres and bynden hem to the Nekke of a Colver and leten the Colver flee, and the Colveren ben so taughte, that thei flun with the Lettres to the very place that men wolde send hem to. For the Colveres ben norrysscht in the Places Where thei been sent to, and thei senden them there, for to beren here Lettres, and the Colveres retournen agen, where as thei ben norrischt, and so thei dou commonly." While, long before, Pliny had referred to it in his _Natural History_[23] as follows: "In addition to this, pigeons have acted as messengers in affairs of importance. During the siege of Mutina, Decimus Brutus, who was in the town, sent despatches to the camp of the Consuls, fastened to pigeons' feet. Of what use to Antony, then, were his entrenchments? and all the vigilance of the besieging army? his nets, too, which he had spread in the river, while the messenger of the besieged was cleaving the air?" The pace of railways; steam communication across the Atlantic; the Suez Canal[24]; were not all these considered in former days to be impossible? With these examples of failure of judgment before us, it may be fairly asked whether, in applying our minds to the investigation of the reality of creatures apparently monstrous, we duly reflect upon the extraordinary, almost miraculous, events which incessantly occur in the course of the short existence of all animated nature? Supposing the history of insects were unknown to us, could the wildest imagination conceive such a marvellous transformation as that which takes place continually around us in the passage from the larva through the chrysalis to the butterfly? or human ingenuity invent one so bizarre as that recorded by Steenstrup in his theory of the alternation of generation? We accept as nothing marvellous, only because we see them daily, the organization and the polity of a community of ants; their collaboration, their wars, and their slaveries have been so often stated that they cease to astonish. The same may be said of the marvellous architecture of birds, their construction of houses to live in, of bowers to play in, and even of gardens to gratify their sense of beauty.[25]