The complementary characters to which we have alluded in our bird’s-eye view of the curio market are liable to exchange their functions according to the moral principles directing their actions, and in this peculiar chameleon-like attitude change colour and hide, from friendship to enmity, assisting the collector in his pursuit, namely, of helping the dealer to dupe him. In broad terms they include art critics, experts, go-betweens and many metamorphoses of the most variegated agents. To these forces must be added the silent help that is generally operative in favour of the dealer. These are drawn from the multiform and numerous guilds of the restorer, and from the questionable side of the trade, namely, fakers, assumed owners, noblemen or pseudo-noblemen willing to lend paternity and pedigree to works of art, smugglers and other degenerate forms of criminal and semi-criminal activity. Speaking of the friends and enemies of the collector whose co-operation is more or less openly apparent and of a less mysterious character, it may be said that the art critic and expert once represented two entirely distinct forms of interest in art. A certain recent evolution of the art critic tends to intermingle the two groups. The art critic of years ago was, as a rule, either a literary man who had a notion that he knew all about art by simple instinct, or a scholar who, having studied the historical part of art, imagined that this knowledge was more than sufficient to label him a connoisseur. The victims of this misunderstanding were not only the art critics themselves but museums and public institutions trusting to their knowledge of art and giving them posts as curators or advisers, thus throwing their gates wide open to faking--as erudition without eye or experience seems to possess that deceitful form of suggestion which so rarely affects the cold, keen intuition of the real connoisseur. That scientists fall an easy prey to suggestion and are prone to daring or misleading hypotheses in art or archæology is beyond question. It is perhaps in the nature of their analytical work to tend to remain purely and simply analytical. Numerous and interesting anecdotes could be repeated. A case of archæological suggestive fancy is told by Paul Eudel. A piece of pottery was brought to a member of the _Académie des Inscriptions_ as it bore a rather cryptic sequence of letters that had proved puzzling to other authorities. The pot with the letters in question, M. J. D. D., had been excavated near Dijon. As soon as the _Academicien_ saw the letters he had no hesitation in pronouncing it to be a Roman vase, a small amphora used as an ex-voto. The letters, he said, represented the initials of the Latin invocation:-- MAGNO JOVE DEORUM DEO.