Page:The American Cyclopædia (1879) Volume VIII.djvu/730

 712 HIBBARD HIBERNATION brethren in Martha's Vineyard. He succeeded in making a number of converts among them, notwithstanding the menaces directed against him by the Indian priests. In August, 1670, an Indian church was formed at Martha's Vineyard, and Hiacoomes became its pastor. HIBBARI), Freeborn Garretson, an American clergyman, born in New Rochelle, N. Y., Feb. 22, 1811. At the age of 18 he entered the ministry of the Methodist Episcopal church in the New York conference, and continued in this work, chiefly in western New York, from 1830 to 1860, when he was elected editor of the "Northern Christian Advocate" at Au- burn. In 1864 he resumed the active pastorate. Dr. Hibbard's principal works are : " Baptism, its Import, Mode, Efficacy, and relative Order " (New York, 1841) ; " Geography and History of Palestine" (1845); "The Psalms, chronolo- gically arranged, with Historical Introductions, and a General Introduction to the whole Book " (1852); and "The Religion of Childhood, or Children in their Relation to Native Depravity, to the Atonement, to the Family, and to the Church" (1864). He has also edited "The "Works of the Rev. Leonidas L. Hamline, D. D." (1872). HIBERNATION (Lat. hibernare, to stay in winter quarters), generally understood as the condition of lethargy, in which many animals Sass the cold season. The sources of their aily food being at this time cut off, they sink into a deep sleep, in which nutriment is un- necessary, and so remain until the warm weather of spring ; a remarkable provision for the preservation of animals which would oth- erwise perish from cold and hunger. Among the animals in which this state has been no- ticed are the bat, hedgehog, dormouse, hamster, marmot, and other rodents ; chelonians, sauri- ans, ophidians, and batrachians ; and some fish- es (like the eel), mollusks, and insects. The phenomena of hibernation, however, are not confined to the winter season, and are not necessarily connected with a low degree of ex- ternal temperature; the bats, in the summer time, present these phenomena regularly every 24 hours; the tenrec, a nocturnal insectivo- rous mammal, though living in the torrid zone, according to Cuvier, passes three of the hot- test months of the year in a state of lethargy. The influence of cold in producing this state is due only to its tendency to cause sleep, and if carried too far, instead of inducing the physio- logical condition of hibernation, leads to the pathological one of torpor, and even death. According to Marshall Hall (" Cyclopaedia of Anatomy and Physiology," article " Hiberna- tion"), the quantity of respiration is inversely as the degree of irritability of the muscular fibre, the former being measured by the amount of oxygen inspired, and the latter by that of the galvanic force necessary to demonstrate its existence. Birds have a high respiration and a low muscular irritability ; reptiles, on the con- trary, have a high degree of irritability and a low respiration. This is true also of the pro- gressive development of animals from the im- mature to the perfect state, in which the change is from a lower to a higher respiration, and from a higher to a lower muscular irritability. In sleep, and especially in the profound sleep of hibernation, the respiration is diminished and the irritability increased. Sleep and hiberna- tion are similar periodical phenomena, differ- ing only in degree, and the latter is extraordi- nary only because less familiar than the former ; the ordinary sleep of the hedgehog and dor- mouse, and of the bat in summer, is a diurnal hibernation, ceasing daily at the call of hun- ger, and accompanied by a diminution of respi- ration and animal heat; and this sleep may pass into true hibernation as the blood becomes more venous in the brain, and the muscular fibres of the heart acquire increased irritability. In perfect hibernation the process of -sanguifi- cation is nearly or entirely arrested ; the bat takes no food, and passes no excretions from the intestines or kidneys; but the dormouse awakes daily, and the hedgehog every two or three days, in a temperature of 40 to 45 F., and they take food and pass excretions, and sub- side again into their lethargy. Respiration is also very nearly or entirely suspended in perfect hibernation, as has been experimentally proved by the absence of all external respiratory acts, by the unchanged condition of the sur- rounding air, by the diminution of the animal heat to that of the atmosphere, and by the ca- pability of supporting the entire privation of air or the action of carbonic acid and other ir- respirable gases. The circulation, though very slow, is continuous, and the heart beats regu- larly ; the blood, from the absence of respira- tion, is entirely venous, bnt the increased mus- cular irritability of the left ventricle of the heart permits it to contract under the slight and usually insufficient stimulus of a non-oxy- genated blood ; it is the exaltation of this single vital property which preserves life and renders hibernation possible, forming the only excep- tion to the general rule of the circulation in animals which possess a double heart ; the slow circulation of a venous blood keeps up a state of lethargy induced by a diminished res- piration. Sensation and volition are quiescent, as the brain and its sensory ganglia are asleep, but the true spinal or excito-motory system is awake and its energies are unimpaired, as is shown by the facility with which respiration is excited by'touching or irritating the animal ; muscular motility is also unimpaired in this state ; the action of the heart has been found to continue about ten hours in an animal in the state of hibernation, in which the brain had been removed and the spinal marrow destroyed, while in the same animal in a natural state it ceases after two hours. "With such an irri- table condition of the heart, the introduction into it of an arterial or oxygenated blood from respiration would soon cause death from over stimulation; and as trifling causes are sufficient