A good collection of these pots would be of considerable interest, but the value attached to them by their native owners is out of all proportion to their intrinsic worth, and makes them difficult to procure. An important series, however, of the Philippine jars has been formed by the Field Museum at Chicago, and they are described with full illustration in one of the excellent publications of that institution.[419] Among other things we are told that "every wild tribe encountered by the writer in the interior of Luzon, Palawan, and Mindanao possesses these jars, which enter intimately into the life of the people. Among many the price paid by the bridegroom for his bride is wholly or in part in jars. When a Tinguian youth is to take his bride, he goes to her house at night, carrying with him a Chinese jar which he presents to his father-in-law. The liquor served at ceremonies and festivals is sometimes contained in these jars, while small porcelain dishes contain the food offered to the spirits."[420] A general similarity in form is noticeable in the Philippine jars, an ovoid body more or less elongated being common to all, while the neck varies a little in its height and width. A series of loop handles or pierced masks on the shoulder, to hold a cord for suspension, is a constant feature. The older types, which are said to date back to a period ranging from the thirteenth to the fifteenth century, are frequently decorated with one or two large dragons coiling round the sides, and either modelled in low relief or incised in the body. Others are quite plain, and the glazes include black, brown, dark green, and a brownish yellow of varying depth. A later group, not older than the end of the Ming dynasty, is without ornament, but coated with single-colour or variegated glazes of the Canton and Yi-hsing types--e.g. speckled blue with green flecks, green with blue streaks and lines, blue and green mottled and crackled, light bluish green--the glaze often ending short of the base in an even line, which is, perhaps, characteristic of Yi-hsing.