REPTILES. 



which have been cut off from the body, as iii the tail 

 of the water newt, and in fragments of the blindworni, 

 may be explained upon the fame principles." Handbuch 

 der Naturgefchichtc, ed. 6. } 98. p. 221. 



The clofe conneilion between the brain, heart, and lungs 

 in warm-blooded animals, in conlequence of which the cef- 

 fation of aftion in one very fpeedily (tops the others, and 

 confequently brings on general death, has been fully ex- 

 plained in various articles of this Diftionary ; viz. Death, 

 Heart, Lunos, Nervous S^^flem. 



Obfervations ai.'d experiments have not yet been fuffi- 

 ciently multiplred, to enable us to underltand all the minutia; 

 connefted with this fubjeft. But obvious phenomena, 

 which we have already alluded to, (hew us a vaft difference 

 in this refpedl between mammalia and reptiles. The inter- 

 ruption of relpiration, which is fatal in two or three minutes 

 in the human fubjeft, does not Hop the aftion of the heart 

 and brain until after fome hours in reptiles. The removal 

 of the heart, or of all the blood from the circulating fyllem, 

 does not prevent the aftion of the brain, and thus prove 

 fatal, until after fome hours. And, laftly, the removal of 

 the wliole brain, or decapitation, which, by interrupting the 

 aftion of the mufcles employed in breathing, is almott. fud- 

 denly fatal in warm-blooded animals, does not very greatly 

 afFeft reptiles. At lead, they only fcem to die from inani- 

 tion after the operation. Hence breathing cannot be under 

 the immediate influence of the brain in thefe animals, for its 

 interruption is fatal in a few hours. Le Gallois alferts that 

 death follows much more quickly, when decapitation is 

 effefted below the occipital foramen, than above it, becaufe 

 in the latter cafe the part of the brain is left, which he has 

 alferted to be neceflary to refpiration ; w'z. the origin of 

 the eighth pair. (See his Experiences fur le Principe de 

 la Vie, p. 42.) He does not, however, afford us the mate- 

 rials of drawing any accurate comparifon, and he allows, 

 that when decapitation is performed in the iirlt vertebra of 

 the neck, the animal furvives the operation much longer 

 than it can furvive the interruption of refpiration. He 

 fays, that falamanders live three or four months, and feem 

 to die only from inanition, when decapitation has been per- 

 formed above the foramen magnum. 



To the fmall influence of the brain upon the nerves, Blu- 

 menbach is inclined to refer, in fome degree, the low 

 temperature of reptiles. Although he confiders it now as 

 certain, that the lungs are the fource, and the oxygenous 

 part of the atmofphere the material, whence the heat of 

 living animals is derived, he afcribes to the aftion of the 

 nervous fyftem a confiderable influence in exciting and fup- 

 porting the evolution of animal heat. Specimen, p. 22. 



The brain feems to exercife as complete and prompt a 

 dominion over the voluntary mufcles in thefe, as in warm- 

 blooded animals. Their motions are equally lively, and 

 the force of contraftion does not feem at all inferior. 



We know of very few fafts that throw light on the intel- 

 leftual faculties of reptiles. Yet there is fufficient evidence 

 of their pofleffing memory and a capability of inftruftion. 

 The frog and tree-frog can be taught to feed from the 

 hand ; and acquire a flight attachment to their mafter. 

 (Daudin, v. 8. p. 88.) The rattlefnake, the hooded-fnake 

 (col. naia), the boae, and the coluber natrix in Europe (at 

 lealf commonly in Germany), are taught to dance, and ex- 

 hibit various motions at command. ( Kaempfer, Amcenitates 

 Exoticje, p. 565.) In the hillorical accounts of the religion 

 of ancient Egypt, we learn that the prieils of Memphis 

 bred up crocodiles in their temples, and fucceeded fo far 

 in depriving them of their ferocity, as to employ them in 

 wligious ceremonies. Befides the accounts of Herodotus, 



5 



Strabo, S:c. on this fubjeft, we have the authority of a 

 refpeftable eye-witnefs concerning very furprifing fuccefs in 

 tamirig a crocodile ; fee J. Greaves's Mifcillaneous Works, 

 p. 525 : and for the like fuccels in the common toad, fee 

 Blumenbach, Specimen, &c. p. 27. We know not on 

 what grounds the fcrpent gained his charafter for wildom, 

 inteUigence, forefvght ; why he was felefted as an emblem 

 for the goddefs of prudence, or chofen by the Epidaurians as 

 the reprefentative of Efculapius. 



Of the artificial inlUnfts, which are fo frequent in the 

 mammalia and birds, not even a trace is to be met with iu 

 the whole clafs of reptiles. 



There is no regular Jleep, or intermifllon of aftivity, in the 

 organs of fenfation and voluntary motion, recurring at Hated 

 intervals, in reptiles : unlefs, perhaps, in the turtles, of 

 whom it has been reported by fome. 



Whiter Jleep, on the contrary, feems to prevail through the 

 whole clafs. Herodotus obferved this of the Nilotic cro- 

 codile, which, he fays, palles four months of the winter 

 without eating. Catefljy has remarked it of tlie crocodile 

 of Carolina ; and Lacoudreiiier reports, that thofeof Loui- 

 fiana betake themfelves to the muddy marlhes when the 

 cold comes on, and remain fo torpid, that they may be cut 

 without (hewing iigns of fenCbility. But the warm days 

 of winter re-animate them. Journal de Phyfique 1782, 

 t. 20. p. 333. 



No animals, except infefts, are fo fenfible to heat 

 as reptiles. The warmth of the fun feems to give them 

 new life : as it increafcs, their vivacity and agility are aug- 

 mented. Cold, on the contrary-, benumbs them, and would 

 be aftually dellruftive, if they did not withdraw from its 

 pernicious influence. They retire into the crevices of walls 

 or rocks, the hollows of old trees, holes in the earth, or the 

 bottoms of ponds, &c. to await the return of the genial 

 feafon. The phenomena of this winter fleep are the fame 

 in reptiles, as in warm-blooded animals. The fufpenfion 

 of the aftions of the nervous fyftem is followed by an uni- 

 verfal torpor of the other funftions. As the brain and the 

 organs of voluntary motion become inaftive, the circulation 

 languifhes, refpiration is barely continued, and vital tem- 

 terature is reduced to the lowefl: degree. 



Spallanzanl found that when the temperature was reduced 

 to i^° below zero, the heart of a ferpent beat only twice in 

 a minute, and refpiration was fufpended. ( Rapports de 

 I'air avec les etres organifes, t. i. p. 230.) In a tempe- 

 rature of 7°, the heart foon recovered its aftion, and beat 

 ten or twelve times in a minute : in Itiil higher temperatures, 

 the pulfations were 28 or 30 /i^r minute. (Ibid.) In the 

 lethargic ftate, thefe animals changed the air very little. 

 Frogs became equally lethargic in reduced temperatures; 

 the heart beating very flowly, and the air being flightly 

 changed. Ibid. p. 470. 



Cold appears to be the immediate caufe of this winter 

 torpor ; hence both reptiles and warm-blooded animals may 

 be preferved in fituations artificially warmed throughout the 

 period of their winter fleep, without becoming torpid ; but 

 if the torpidity has commenced, they cannot be artificially 

 awakened without danger. It is well known that the 

 falamander, the water-newt, the tree-frog, and the alpine 

 marmot, may be kept awake through the winter in a room 

 warmed by a ftove. Gleditfch witneffed the fatal effefts 

 of violent excitement in the winter ileep in the frog (Mem. 

 de I'Acad. de Berhn, 1762, p. 17.): it has been obferved 

 alfo in the marmot, the dormoufe, and the fwallow. 



It may be remarked further, of warm-blooded animals, 

 as well as reptiles, that fome fpecies affemble together, and 

 are gregarious in their torpidity, while others are fohtary. 



The 



