Stagnation takes place in sluggish bowels. As a general rule, fæcal movement is caused by peristalsis of the intestines, which consists of circular contractions of the bowel by which the contents are propelled toward the end of the same; besides these movements there are also pendular or vermicular contractions of certain parts of the intestines; all these movements also assist the admixture of the chyme with the juices of the intestines. All these contractions are caused by impulses from the nerves which lie in the walls of the intestines, the plexus myentericus; they can also be provoked by impulses coming from the central nervous system. The nerve ganglia that lie in the walls of the intestines can be influenced mechanically by the contents of the intestines, when such are bulky, and also when they are fermenting; therefore, the bacteria, by promoting fermentation, also aid in peristalsis. The bulky condition of the bowel contents can be best induced by food of the vegetable kingdom through its cellulose contents, of which tissue the cells of plants or fruits are largely formed. When these irritating agents act on the nerve filaments in the intestines, the bowel will contract and expel its contents. But when food contains no irritating substances and is easily assimilated without forming _residues_, or when the innervation by the vagus is sluggish and the peristaltic movements are slow, the contents of the intestines can remain longer, especially in the haustra of the intestines. It may be that the bowels move every day, but that does not prove that everything in the intestines has been expelled therefrom, for some amount of fæces can yet remain in the haustra of the intestine even for many days; so that in such cases there is still a constipation of one part of the bowels. We have observed, personally, and on patients, that, after a good opening of the bowels, when a purge is given—for instance, directly after a meal—a short time afterward there has been another copious discharge that had evidently remained behind. Thus, no doubt a retention of fæces, and sometimes a condition analogous to auto-intoxication, can be caused in people who have the bowels opened every day, although not to the extent of those having obstruction or habitual constipation. To avoid such a condition a good purge should be taken at regular intervals, say once a week, even by persons who have a movement daily, in order to eliminate matter which may have remained. It will not be necessary, naturally, to use a too powerful purgative, but one adapted to the necessity of the case; taking, as a rule, such a purge as will act a little better than the ordinary bowel movement, and graduated according to the strength of the person so using it.