Associated or not with palpitation, irregularity in the force or frequency of the heart beats is sometimes met with at intervals or independently of any further indication of structural disease. Particularly in the greyhound and certain other breeds of dogs the temporary occurrence of intermitting action of the heart is a frequent though a very transient condition. It may be excited by some emotion or excitement such as the attentions of the owner, or the straining anxiety in the immediate anticipation of the chase. Here again digitalis is pronounced the great panacea though it need not be resorted to unless the habit interferes with the usefulness of the animal. If in any degree dependent on weakness, that must be counteracted by a systematic tonic treatment. CONGENITAL MALFORMATIONS AND DISPLACEMENTS OF THE HEART. Ectopia Cordis. Cyanosis, pervious foramen ovale. Symptoms, blue mucosæ, coldness, staring coat, unthriftiness. Unequal to exertion, palpitations, murmur before the first heart sound. Obstructed circulation in the lungs as a cause of cyanosis, cyanosis as a cause of lung disease. These have been much less frequently observed in the lower animals than in man. The anomalies observed in mammals include the following: The displacement of the heart to the right side of the chest; displacement entirely out of the chest (ectopia cordis); permanent communication between the right and left auricles (cyanosis); entire absence of heart; two hearts; one common ventricle communicating with two auricles as in reptiles; three ventricles; only one auricle; absence of one or several valves; absence of the pericardium; variations in the mode of connection of the heart and large vessels, etc. =Displacements of the heart= have been especially studied by Hering on calves. The breast bone remained as originally developed in two lateral halves, and the heart remained outside connected with the interior of the chest only by its large vessels. The heart thus exposed and covered only by its investing membrane (pericardium) afforded an excellent opportunity to study its action, of which Hering freely availed himself. Animals affected in this way survived their birth but a very short time. An approach to this condition was thirty years ago made familiar to the medical world in the person of M. Gouz, a German mechanic, the movements of whose heart could be easily watched through a fissure in the breast bone.