Page:The New International Encyclopædia 1st ed. v. 16.djvu/616

* PULMONATA. 538 PULSE. with a contractile 025eniiig- under the margin of the mantle. Those forms which live in the water jire obliged to obtain their air supplj' at the sur- face. The licart has only one auricle and that usually lies in front of the ventricle. The nerve cords connecting pleural and visceral ganglia are not crossed. The I'ulmonata are either land or fresli-water forms, except Onchidiuni. They are all hermaphroditic. The number of known species runs u]) into the thousands, and though they are found in all temperate regions, they abound es- pecially in certain tropical islands, as Jamaica and the Hawaiian Islands. In America the order is represented l)y many species of land-snails, slugs, and pond-snails. Few species reach a large size, and most have rather plainly colored shells. See Snail. PULPIT (from Lat. puJpitum, platform, rostrum). A piece of church furniture used for the delivery of sermons. In the first Christian ages, when the bishops were practically the only preachers, they delivered their addresses from the episcopal throne at the end of the apse ; hence a pulpit is called chaire in French to this day. Then the ambo (q.v. ) was sometimes used for this pur]iose, and later the jube or rood-loft between the clu)ir and nave. 13y the eleventh or twelfth century small movable pulpits had been introduced, which could be Ijrought out at the time of the sermon; and by degrees the mod- ern pulpit, generall}- on one side of the nave, was evolved. There are some excellent mediieval ex- amples in Italy, especially that by Benedetto da Majano in Santa Croce at Florence, two very fine ones by Niccola Pisano at Pisa and Siena, and another by his son Giovanni at Pistoja. The most ancient pulpits extant in France are sup- posed to be not earlier than the fifteenth century. Admirable examples of wood-carving are those of Saint Etienne du Mont and Saint Germain I'Auxerrois in Paris, and Sainte Gudule in Brus- sels. Another notable one was made for the Cathedral of Strassburg by .Joh.ann Hammerer at the end of the fifteenth century. PULQUE, pul'ka (Sp., from Aztec octU) . A favorite beverage of the Mexicans and of the in- habitants of Central America and some parts of South America. It is made from the juice of different species of agave (q.v.). PULSATILLA. See Anemone; Pasque Flowek. PULSE (Lat. pulsus, a beating, from pellcre, to drive). The rhythmical expansion of the arter- ies due to the blood-waves caused by successive contractions of the heart. The arteries are elas- tic tubes and there is injected into them at each contraction of the heart ventricles from two to four ounces of blood. As a consequence, an al- ready full but contracted artery becomes dis- tended, lengthened, and uplifted, giving rise to the sensation in the examining finger which is called the pulse. The pulse-wave due to any given beat of the heart is not perceptible at the same moment in all the arteries of the body. The difference in time is proportioned to the distance of the arteries from the heart, and rarely amounts to more than ^/^ or ig of a second. The pulse is usually felt at the radial or thumb side of the wrist, the artery being near the surface at this point and easily compressed against the bone. It may, however, be perceived in many other situations, notably at the point where the facial artery crosses the lower jaw, in the tem- j)oral artery above the ear, the carotid in the neck, the brachial in the arm, and the femoral just below the fold of the thigh. The pulse rate varied greatly in health accord- ing to age, se.x, temperament, exercise or rest, emotional states, temperature, time of day, pos- ture, atmospheric pressure, and personal idiosyn- crasy. Before birth the average number of pul- sations per minute is 150; in the newly born, from I-IO to 130; during the first year of life, 130 to 115; during the second year, 115 to 100; about the seventh year, 90 to 85; about the 14th year. 85 to 80; in adult life, 80 to 70; in old age, 70 to GO ; in decrepitude, 75 to Go, In the female and in persons of a sanguine temperament the pulse rate is more rapid oy several beats in the minute than in males and individuals of a phlegmatic type. The rate is also higher after a meal and during exercise. The pulse is most frequent in the morning and becomes gradually slower as the day advances; it is more rapid in the standing than in the sitting or recumbent posture; high temperatures also accelerate it. Dui-ing sleep the pulse is usvially slower than in the waking state. Forty is not an uncommon rate, and instances have been known in which- file jiulsations were only 30 or more rarely 20 to the minute. In disease the pulse presents wide variations in rate, regularity, volume, and tension, and is a valu.ablc guide in diagnosis and in estimating the physical condition of the patient, and disturb- ances of its relation to respiration and tempera- ture are always significant. Excessive slowness of the jjulse (bradycardia) occurs in some dis- eases of the heart, in conditions of collapse, in meningitis, in cerebral tumors, and in jaundice. It is also observed in convalescence from acuta fevers and is probably an expression of exhaus- tion. As a physiological phenomenon brady- cardia occurs in the puerperal state, and in hun- ger. As a general rule in disease the pulse is more apt to be abnormally fast (tachycardia) than slow. Nearly every disturbance of health tends to quicken the pulse; rapid heart action is the constant accompaniment of acute inflam- mation, of fever in all forms, and of most heart diseases. When the intervals between successive beats of the heart are not of uniform length, the pulse is said to be irregular. A pulse inter- mils when a beat is dropped out of every four or more pulsations. Another form of irregularity is known as the pulsus higeminus or allarythmia. In this the beats occur in successive pairs with an abnormall.y long interval between them. Pul- sus paradoxus consists in the diminution or total disappearance of the pulse during inspiration, and is a very rare occurrence. The pulse is said to be full when the volume of the pulsation is greater than usual, and it is called small or contracted under the opposite con- dition. Fullness may depend on general plethora and on prolonged and forcible contractions of the left ventricle of the heart ; a small pulse results from general deficiency of blood, from feeble ac- tion of the heart, congestion of the venous sys- tem, or exposure to cold. When very small it is termed thread-like. The tension or hardness of the pulse is the property by which it resists compression. A hard pulse can scarcely be stopped by any degree of