No abstract

No abstract

No abstract

No abstract

Since Liesegang1 called attention to the phenomenon which bears his name, in 1896, a considerable literature, now numbering well over three hundred titles, has accumulated on the subject. This study has extended into geology; physiology; botany; bacteriology. It includes "rhythmic" phenomena observed in solids, liquids, and gases, and "periodic precipitates" as various as:rings of trees; mother of pearl; bone structure; drops of chloroform; drops of mercury; gas bubbles; shell structure; markings on butterflies' wings; rhythmic settling of sediments; etc., as well as precipitates more or less periodic in nature, of slightly soluble substances formed by metathesis in gels of gelatin; agar; starch jelly; fruit jellies; silicic acid; etc., and in inert