It is as yet too soon to state what corrections or additions should be made to the various figures I gave in my Population of Athens as a result of new evidence since that book was published (1933), although some individual discoveries have been made and Sterling Dow has published his invaluable Prytaneis (Hesperia, Suppl. I, 1937); for the excavations in the Athenian agora are not finished–though it looks as though the hopes I expressed for the discovery of a large number of inscriptions that would throw new light on the problem will be disappointed. But two objections have been made to my treatment of the number of slaves in Athens, by Mr. Hammond in Proc. Camb. Phil. Soc, 1935, p. 1, and by Prof. George Thomson in his edition of The Oresteia, I 70, n. 1 and II 357-9, both of whom maintain that Ktesikles' figure of 400,000 must be accepted; and though the question has again been discussed, convincingly enough to my mind, by Prof. Westerraann in Athenian Studies (Harv. Stud, Suppl. Vol. I, 1940, 451-70), it is worth dealing with certain aspects afresh, especially in answer to Thomson, for some important principles are involved. Not that anything I can say will convince him; for he hopes that ‘the whole subject will be re-examined by someone who is prepared to take the ancient evidence seriously and is free from the suspicion of seeking to minimise the extent of an evil which casts a sinister shadow over the glory that was Greece.’ But I will do my best.