Page:The New International Encyclopædia 1st ed. v. 10.djvu/65

* HIAWATHA. 51 HIBEENATION. is owned hy the city. Population, in 1890, 2486; in l!l(», •282!t. HIAWATHA, hi'a-W8'ta or -tha. A narrative liocni hy lluiiry U'ajsworth Longfellow, founded on an Indian Irguiui preserved in IScliocjlci-aft's Altfic licsearchcs, and History, Crmdiliuii, and I'rospects of the Indian Tribes of the United •States. However, the miraculously born hero is declared to be an Iroquois and not an Ojil)way, according "to other sources. Longfellow adopted tlio metre of the Finnish epic Kiilerahi. and was accused of taking the entire plan from that poem. But the incidents common to both show merely the recurrence of early myths. HIB'BERT LECTURES, The. A course of lectures given aiuiually in London, discussing some unsettled problem in religion or theology. The lectures are supported from a fund left by Kobert Hibbert, a Jamaica mercliant, who died in 1S4!), leaving liis property in trust for the promotion of scholarship, particularly among Unitarians. By a wise provision the trustees were emi)owered to revise the terms of adminis- tration from time to time, and in the exercise of this power they established the lectures in 1878. The first series was delivered in that year by F. Max Miiller on "The Origin and Growth of Religion," and succeeding series have been given liy Kuencn. Beard, rvcville. Page Renouf, Renan, Rhys D.avids, Ptleiderer, Rhys, Sayce, Hatch, and others. HIBERNATION (Fr. hibernation, hiverna- tion, from l.at. iiitirrnare, to hibernate, from hi- hcrnus. winter, from hiems, winter, Gk. %iii», chiOn, Skt. hima, Av. zima, winter), and Estiva- tion (Fr. estivation, from Lat. (rstivnre, to pass the summer, from wstivus, pertaining to the summer, from wstas, summer: connected with Lat. cesttis. heat, Gk. atdeiv, ailhein, to burn, AS. iid. funeral pile, Skt. idh. to kindle). A physio- logical state of dormant vitality in which many animals in northern countries are able to pass the winter. It should not be confused with the torpor of freezing, which is a pathological and usually a fatal condition. The immediate cause of hibernation is not cold, for many animals go into their winter sleep some time before winter is on. Nor is it the lack of food, for the great l)at begins sometimes to hibernate as early as the end of .Tuly, at a time when its insect food is still al)vnidant. ^loreover. the winter season is not the only one passed oy animals in this kind of torpor. Tn dry countries, at the a])])roach of the dry seas(m, when moisture, lu'rbage. and consccpiently animal food will be scarce, many kinds of animals are enabled to survive until the time of plenty again by going into a pro- longed stupor, which seems not to be very difTcr- ent in kind or duration from the hibernation of northern forms. The Germans have for these two conditions the words 'Winterschlaf (winter sleep) and 'Sommcrsclilaf (summer sleep). The latter state is known in English a,s 'estivation.' DoR^rA^'T Vttai.tty. or 'rigor,' is a term used for an apparent suspension of vital activity, distinguished from death by the possibility of resuscitation. Two general classes may be dis- tinguished: (1) Dormant vitality induced by external conditions; and (2) dormant vitality determined by internal conditions. The first class is of three kinds: (n) Desirentinii riqnr. There are certain animals, notably rotifers, tar- digrades, and nematodes, which can be dried in a vacuum until they heccjme immobile, and can remain thus immobile for days or even months until, on the addition of water, they become active again. The organism has probably not lost all of its water, but has passed into an encysted condition; it is not dead, but its metab- olism is greatly reduced. Even snails and other animals which can protect their internal tissues from C(jm))lete loss of water may live for months willumt showing external activity. {b) Dark riijor is in<luced in green plants and even in certain fungi by their removal for several days from the light. The .sensitive plant treated thus becomes immobile. Light is essential to move- ment. The reverse, or "light rigor," has been seen in bacteria, (c) Heat rigor. — The sensitive plant, muscle, and various other forms of protoplasm become quiescent at a temperature a few degrees below that at which they are killed by heat. The rigor seems to be due to the beginning of the death changes. Cold rigor occurs in simple protoplasm as it approaches the zero (centi- grade) temperature. The chlorophyll granules of Vallisneria mive only about one mm. per minute at 1° C, and not at all at 0°; the rotation of Nitella ceases at 0° Cf. ; in Tradescantia hairs, movement is wholly arrested on freezing the cell- cap. Even in seeds and bacteria, which are not killed by the lowest temperatures, all vital activi- ties have probably ceased at 0". for De CandoUe found that iu only one species out of ten could he get a seed kept at 0° to germinate, and even then germination was so retarded that it took from 11 to 17 days as opposed to 4 days at 5.7°. Likewise, bacteria do not multiply below .5° to 10°. Among animals Kuhne found .Amceba cooled to near 0° almost motionless. Purkinje and Valentin first noticed that the ciliated epithe- lium of the frog ceased its movements at 0°. Muscles of the frog were fouiul by Kuhne to become at — 3° to — 7° a solid lump, which did not, however, wholly lack irritability. The evi- dence of all these cases shows that activity nearly ceases in protoplasm at or near 0° C. Determined by internal conditions, seeds, rest- ing spores, cysts, gemmules of sponges, and stato- blasts of Bryozoa are all conditions of natural clorin:int vitality. The period of dormancy is not unlimited, however, the alleged germination of seeds many hundred years old not being con- firmed. This indicates that even with a slow rate of living the food material eventually be- comes exhausted. Belief in himian dormancy rests largelv upon a certain collection of cases obser'ed in India and published by James Braid. PUKiNO.MENA OF HlUFRXATION AND ESTIVATION. The physiological facts mentioned above nuist be .considered in studying the phenomena of habitual animal dormancy Tinder conditions of winter, seasons of drought, and so on. The respiration in winter sleep is diminished much more than in ordinarv sleep, and consequently the heart-beat is very slow. The digestive orirans are practical- Iv inactive. ^lany animals void almost no ffpces during this period, and the anal opening of those bears that hibernate is closed by a resinous plug known to hunters as the 'seal.' The temperntiire if the bodv is lowered to that or nearly that of the air. The voluntary- control of the muscles is lost, but there is an increased muscular irri- tabilitv. an unusual sensitiveness to external