34 



THE EDINBURGH JOURNAL OF NATURAL HISTORY, 



ON THE HYBERNATION OF ANIMALS. — NO. I. 



It is a remarkable fact, and one which has attracted considerable attention, that while 

 many animals migrate to a more genial climate when the cold of winter approaches, 

 others betake themselves to some hiding place, where they fall into a deep lethargy, 

 in which they remain until the revival of spring. This state is usually designated by 

 the term Hybernation, and is best marked among the Insects, the MoUusca, the Rep- 

 tiles, and a few of the Mammalia. In all probability it occurs also in a considerable 

 number of Fishes; indeed it seems absolutely necessary for the preservation of many 

 of them during the winter, in cold climates, when the surface of the lakes is frozen 

 over for months together. This state is apparently intimately connected with the 

 preservation of the individuals subject to its influence, under circumstances where 

 they would otherwise find it difficult or impossible to exist, and it has therefore received 

 from Mangili the appropriate term of the Conservative Lethargy. According to 

 Humboldt, a lethargic state similar to hybernation is also induced in some animals 

 under the influence of a tropical heat. 



The hybernating animals belonging to the class Mammalia resemble the other ani- 

 mals of that class in every other respect. They possess no uniformity of structure or 

 appearance, by which we might be enabled, a priori, to predict that they would become 

 lethai-gic when placed under certain circumstances. Some belong to the Carnassiers, 

 as the Bats, the Hedgehog, and Tanrec ; a greater number to the Rodentia, as the 

 Marmot, the Hamster, and the different kinds of Dormice. They differ also from 

 each other in the nature of their food. The Bats live on Insects; the Hedgehogs on 

 Worms and Snails; and the Marmots, Hamsters, and Dormice, on nuts, roots, and 

 herbs. Most of them are crepuscular or nocturnal feeders. 



Prunelle denies that the Bear of the Alps can be properly said to liybernate. " No 

 doubt," he says, ** he lies in a drowsy state for days together, but he is never so le- 

 thargic as to allow the hunters to approach him. He also adds that tame Beai-s never 

 become lethargic. It appears, however, from numerous and authentic sources of infor- 

 mation, that the Bears of more northern regions pass the winter in a state of actual 

 hybernation. 



When an animal is examined in this state, it is found to be under the influence of 

 a lethargy more or less deep, and with all its vital actions nearly at a stand. This 

 lethargy only occurs within a certain range of temperature, apparently varying to a 

 small extent in the different hybernating animals of the same country, but probably 

 to a considerable extent in different, or in the same hybernating animals, of dissimilar 

 countries. The Dipus Sagitta is said to become equally lethargic, during the winter 

 months, in Egypt and in Siberia. The Tanrec (Centenes ecaudatus) is also said to 

 remain lethargic for six months of the year in the climates of India and Madagascar, 

 of which places it is a native. 



To produce this state in a Marmot, the temperature must not be raised much above 

 50^ Fah., and should not be carried below the freezing point. When the temperature 

 is lowered beyond this, the animal becomes lively, its respirations and the pulsations 

 of the heart increase in frequency, its animal heat rises, and it endeavours to escape 

 or protect itself from the cold. If it should remain exposed for some time to this 

 diminished temperature, it proves fatal in the same manner as in the other Mammalia, 

 viz. by inducing coldness, torpor, and complete cessation of the heart s action, and 

 other vital functions. This torpor, which precedes death in the hybernating animals 

 when exposed to extreme cold, is quite a different thing from the conservative lethargy 

 peculiar to them; and these must never be confounded in any discussions or experi- 

 ments on this subject. The lethargy resembles a deep sleep, from which the animal 

 may be roused in perfect health, — the other is the failure of the vital functions, which 

 precedes death in every animal placed under similar circumstances. Those who com- 

 pare this lethargy to the irresistible torpor which creeps over the human species when 

 exposed to extreme cold, must entertain very erroneous notions concerning its nature. 

 Mangili, on placing the fat Dormouse (Mi/oxus glis) in a temperature equal to 17^* 

 Fah., found that it struggled to escape; but when placed in a temperature of 48'', it 

 became lethargic. He killed a Muscardin (^Mics, or Myoxus avellanarius) in twenty 

 minutes, by exposing it to a temperature equal to about 8" Fah. He also found, 

 that when Bats were placed in a temperature one degree above the freezing point, 

 they were lively for some time, then became torpid, stiffened, and died. Prunelle 

 killed a Hedgehog {Erinaceus Europmus) by confining it in a temperature of about 

 5^ Fah. for twenty-two hours. He also found that a Hedgehog was lively and fed 

 in a temperature of 41'' Fah., and was dormant when it rose to 50". Marshall Hall 

 states, that when Dormice are supplied with cotton or wool, they become sooner 

 lethargic than those to whom this is denied. In fact, all the hybernating animals can 

 easily be killed by their exposure to severe cold in this manner, and nothing appears 

 more effectual in rousing them from their lethargy than its application, as the experi- 

 ments of John Hunter long ago proved. In this manner we can easily explain 

 the circumstance of the Bat having been occasionally seen flying about houses in the 

 middle of winter. The place to which it had retired for the winter had not been 

 fiufiiciently sheltered to prevent the temperature falling below what was compatible 

 with the lethargic state; it had become roused, and had betaken itself to the wing to 

 look out for a warmer retreat. 



All the hybernating animals instinctively take precautions against the fatal conse- 

 quences of severe cold. They either retire into caverns, into holes, or make nests 

 for themselves. The Bats retire into caverns, hang suspended by their claws to the 

 roofs in clusters, and cover each other with their wings. The Marmots (Arc- 

 iomys marmotta) retire to their holes at the end of September, and reappear at 

 the end of April, As several of them retire to the same hole, and as they stuff the 

 mouths of these with grass and other materials, the temperature can never fall very 

 low. Prunelle states that the temperature at the bottom of their holes is from 46** 

 to 48" Fah. The Hedgehog and Dormice make wai'ra nests for themselves at the ap- 

 proach of winter. 



This lethargy is not generally so profound as many have been led to beHeve. Man- 

 gili states that the slightest disturbance of the animal sometimes causes signs of irrita- 

 bility. Prunelle and Marshall Hall have dwelt upon this as one of the principal 

 difficulties in making accurate observations upon the functions of the circulation and 



respiration in these animals, even while fairly under the mfluence of this lethargy. 

 These signs of irritability are marked by muscular motion, increased respiration, pul- 

 sation, and animal heat. Prunelle also states that they can be roused by electricity, 

 or by the fumes of ammonia apphed to the nostrils. The stories told of dissecting 

 these animals under a state of lethargy, without their exhibiting signs of sensation, 

 must have been entirely a mistake; the authors of them must have confoxmded the 

 state of torpor from extreme cold with that of lethargy. 



This lethargy seems to vary in degree in different animals, and in different indivi- 

 duals of the same species. Mangili descended into the famous Grotto of Entrastico, 

 in the month of December 1775, the temperature of the interior being about 53*' Fah. 

 He discharged a musket near 300 Bats, the Vespertilio murinus of Naturalists, without 

 observing the slightest movement among them. He next discharged a loaded mus- 

 ket among them, and though many fell killed and wounded, those that remained 

 untouched were perfectly quiescent. He returned into the same grotto in February 

 1804, the temperature of the interior being nearly the same as on the former occa- 

 sion. Most of the Bats observed at this visit belonged to the Vespertilio nociula, 

 which visits England during the summer, but retires to Italy to pass the winter in a 

 lethargic state. The light of the torch, on this occasion, was sufficient to make some 

 of them change their places. The same author preserved a IMarmot for two years, 

 which never became lethargic under all the different changes of temperature. M. 

 Bossi kept two Marmots for two years, which were exposed for a time to a tempera- 

 ture from 18" to 20" Fah. without becoming lethargic. 



Prunelle states, that having entered into the ancient aqueducts at Lyons and 

 Vienne several times during the winter, he found, that while the greater number of 

 Bats were in the lethargic state, some flew about as in the middle of summer. In 

 the end of January 1807, he descended into a subterranean passage at Brunette, 

 and found a great number of Bats collected upon the roof, in groups of from ten to 

 twelve in number ; others had placed themselves in holes, the greater part of them 

 lethargic and cold as the stones upon which they rested ; while others still flew about, 

 but very feebly. The temperature of the place was 50" Fah. ; the external air was 

 nearly 39°; the temperature of the animals themselves was from 41" to 63". 



J. R. 



Extraordinary! — The larvs of a certain fly (Eristalis tenax, Meig) will admit 

 of being pressed in a bookbinder's press, as broad and thin as a card, without being 

 killed, when freed from its confinement and restored to its usual dwelling-place, — 

 Dr Hermann Bermeistei-^ s Manual of Entomology. 



BOTANY AND HORTICULTURE. 



GENERAL REVIEW OF THE VEGETABLE KINGDOM NO. I. 



DY C. F. BRISSEAU MIRBEL, MEMBER OF THE INSTITUTE OF FRANCE. 



[The following subjects will be treated of briefly in a series of articles, of which 

 this is the first. 1. The laws which regulate the distribution of the diflerent 

 tribes of plants over the globe. 2. The influence which climate, elevation, as- 

 pect, and soil, have upon these beings. 3. The effect which plants, in their turn, 

 produce on the exterior bed of soil, on the temperature from latitude or position, 

 as well as on the general constitution of the atmosphere.]] 



Multitudes of different species of plants are found spread over the whole surface 

 of the globe. Liko animals, these are endowed with the faculty of increasing their 

 races to infinity ; and difi'er from each other as much by their interior structure as ex- 

 ternal appearance; each has its peculiar wants, and, if we may be allowed the terms, 

 its separate habits and instinct. 



We see that some species belong to the mountains, others to the valleys, and others 

 to the plains ; some affect a clayey soil, some a chalky one, others one of a quartzose 

 nature, while many will thrive in no place but where the soil is impregnated with soda 

 and muriatic salt. There are some that confine themselves entirely to water ; divid- 

 ing themselves again into those of the marsh, the lake, the river, and the ocean. 

 Some require the hottest climates, others delight in mild and temperate ones, others 

 thrive nowhere but in the midst of ice and frost. A large proportion must have a 

 constantly humid atmosphere, several do very well in a ch-y air, but the major part 

 are equally averse to the eistremes of both dryness and moisture. There are those 

 which flourish when exposed to the action of a strong light, while others prefer the 

 weaker action of that element. The result of this variety of wants is, that nearly 

 the w^hole surface of the earth is occupied by vegetation. 



Excess of heat, cold, or drought, a total privation of air or light, are the only bars 

 to vegetation; and yet we find some agamous species (such as are presumed to pro- 

 pagate themselves without the intervention of the organs of fructification) which orow 

 in caverns where the light has never gained admission. 



Seeing that the forms of vegetables are infinitely various, and that certain species, 

 genera, and even tribes, are attached exclusively to particxdar countries; and that 

 this distribution of races, a consequence of the first order of creation, has maintained 

 itself to our day by the effect of climate and situation, without perceptible deviation, 

 ■ — it must he admitted that the soil takes one of its distinctive features from the veo-eta- 

 tion it bears. 



Some species are confined to the narrowest limits. The Origanum Tournefortiiy 

 discovered by Tournefort in 1700, in the little island of Amorgos, upon one rock 

 only, was found 80 years afterwards by Sibthorp, on the same island and upon the 

 same rock; but no one has ever observed it any where else. Two of the Orchidea, 

 Disa lo7igicornis, and Cymhiditnn tabulare, grow upon the Table Mountain, at the 

 Cape of Good Hope; and Thunberg, who has described them, found them on no 

 other spot. 



Mountainous countries afford many of these local species, such as dwell secluded on 

 the heights without ever migrating to the plains below. Thus we find that the Py- 

 renees, the Alps, the Appenines, &c., have their peculiai- Floras, and that even some 

 separate mountains of those great chains have species allotted to them alone, and 

 which are not to be found on the adjoining summits. 



Speculatively, we might presume that all the individuals of one species would esta- 

 blish themselves under the same, or neai'ly the same, degrees of latitude, as thej 



