The normal movements of the intestine have been described by many observers, and in these descriptions there is a fair amount of uniformity. Ludwig and his pupils, Bayliss and Starling, Magnus and others have studied this subject with much care. In such a complicated organ as the intestine there are many sources of error, and differences of opinion may readily arise if an attempt is made to analyze too closely the functions of the various tissues making up the intestine, to decide for example whether the movements are of nervous origin or muscular, or whether the secretion is dependent primarily on the blood supply or on the nervous system. For our purpose it will be sufficient to regard the intestine as an organ composed of certain muscular layers, certain nervous plexuses and certain glands--and to discuss the action of various influences not on these separate tissues, but on the organ as a whole, holding in mind also the nervous and bloodvascular connections of the organ. If the abdominal cavity of a dog, cat, or rabbit be opened under the surface of m/6 NaCl solution or Ringer’s solution at body temperature, it will be found that the intestines are not entirely at rest. According to local conditions, more or less active movements will be seen. These were described by Ludwig and others as consisting of two kinds of motion, namely, the _pendulum movements_, and _peristaltic movements_. The pendulum movements are rhythmical, and consist of a regular slight swinging of the loops upon one another. Their frequency has been measured by Bayliss and Starling.[2] According to these observers, each contraction and relaxation lasts 5 to 6 seconds, so that the rhythm consists of 10 to 12 beats per minute. The rhythm is however not always regular, the contents of the loop and other local conditions exerting an influence. The cause of these pendulum movements is not perfectly clear. By many they have been ascribed to a rhythmical shortening of the intestine, _i.e._, a rhythmical contraction and relaxation of the longitudinal muscle coat. Mall[3] regards them as arising mainly in the circular layer; while Bayliss and Starling state that they are due to simultaneous contractions of the circular and longitudinal coats.