This form of the game exhibits its original meaning. As in several other games of chase, the pursuer represents an evil spirit, from whose attack, according to ancient superstition, iron was a protection. Hence the challenge, in Silesia and Switzerland, is, "Father, I have no iron, hit me."[100] The chaser, it seems, was conceived as the aged but powerful dwarf, of malignant character. Thus we get a vivid idea of the extent to which such representations once affected the lives even of children, and see that an amusement which is now a mere pleasurable muscular exercise followed the direction imposed by belief. There are numerous varieties of this game. In _cross-tag_, the pursuer must follow whoever comes between him and the pursued. In _squat-tag_, the fugitive is safe while in that position, or is allowed a given number of "squats," during which he cannot be touched. A peculiar variety (in Philadelphia) is "Tag, tag, tell a body." In this game every child is forbidden to tell who is "it," on penalty of replacing him. Sometimes the name of the pursuer is kept secret until revealed by his actions, or the child who has been tagged deceives the rest by keeping up his speed. On the other hand, the catcher is sometimes bound to turn his cap inside out, whence the game is called _turn-cap_. "Pickadill" is a kind of tag played in Massachusetts during the winter. A large circle is made in the snow, with quartering paths; if there are many players, two circles are made. There is one tagger, and the centre is the place of safety. "London Loo" is a particular species of the game (in Philadelphia) in which the following: formula is used: "1, 2, 3, 4, 5, 6, 7, 8, 9, 10--London!" "Loo!" "I'll try to catch one of you." No. 104. _Den._ This is an out-of-doors game. Each boy represents a wild beast, and has a separate tree, which represents his "den." Any player who leaves his den is liable to be tagged by any who has started out at a later moment. The best runner usually ventures first, a second pursues him, and so on, until all may be out at once. If a player can tag any one whom he has a right to capture, he takes him home to his own den, and the latter must help him to take the rest. The pursuer cannot be tagged while bringing home his prisoner. _Cambridge, Mass._ No. 105. _I Spy._[101] This game is world-old and world-wide. To judge by the description of Pollux (in the second century), it was then played exactly as American children play it to-day. "One of the party places himself in the middle of his comrades, and closes his eyes, unless some other covers them for him. The players run away and scatter. Then the pursuer opens his eyes and proceeds to look for them. It is each player's object to reach that one's[102] ground before him."