HERPETOLOGV. 



11 



and in one tribe, the crocodiles, is even more 

 complicated than that of the first order. It is in the 

 ed, that it* structure has been most so 

 carately examined, and to this tribe we shall here con- 

 fine ourselves. 



The heart of the crocodile i* situated partly between 

 the lungs, and partly between the lobes of the liver. 

 . are proportionally less than in the CMostseet. 

 but their side* are thicker, and strengthened by fleshy 

 bundles, dl urging m variou* directions. The ventn- 

 efe i* of en oral form, and he* very thkk sides. Itacm- 

 rky is divided into three cuoipaitinssiU, COM 

 fat* with each other by mraoraM ariflese. One of 

 i* Wow. and toward* the right, and 

 with the right soride by large opening contracted by 

 two valve., that direct the Mood through its 

 pert. On the left side of this cavity is the 

 - - distributes 



paaaag* to 

 blood to the 



On the left side of 

 ilarge artery on the left, that 

 eeeralarhmd partaof the body; and behind Urn an 

 orifice lead* to the snail rst of the three compartment*, 

 taaatod at the Middle ef the baee of the heart ; and from 

 thia arises the common trunk of the pulmonary ar- 

 teries. 



Hence the Mood that U poured by the right auricle 

 in-.n the OTBpartmeni on that side, How* chiefly in two 

 direction* ; l*f. Into what nay be called the ngkl tyt- 

 Irmic compartment of the rantrtde. which throw* it 

 into the left ntral eerie . taVy. Into the f sjfssosJsV com- 



... . 



' r\ , 



of it protwbty 000*1 into ihe WA yrte- 



1 hf !r:* ..-;. n t i . r ! '* S i* - I 



from the piihnasssry veins, end poor* it into the left 



ami from thi* latter it i thrown into the 



left Mitsui t artery, the carotids, end axillary arteries appearan 

 The itore. <ifder have a beset extretnefy ample, ther prof 



afeconieeJfonn. from which 

 tonal trunk, that by Us 

 eO pert* of the body. 



her and coerse OF tne nnneipef 



tile tnbes ; but most refer the reader to Cuvser's A ae- 



toe blood to 



of the num. 

 in the rep. 



Jseair CWspereV. Lee. an xxv. Art. 3. vol. iv. where they 



There M net that well 

 ^srt*TialsndvenoMMoodmrcptiUa,i 



in tortoises. It i. Mid that reptile* which have farted 

 long hee the Mood of a paler colour then the seme spe. 

 cie regularly fed. 



The sfcsofate quantity of blood in the 

 system of reptiles, b proportionally 



in -.-..-.,/,,,,., I I..H. . U...t',,,r 



now prepared to consider two of these circumstances 

 the remarkable faculty of reproduction of parts that 

 have been mutilated or destroyed, and the great tena- 

 city of life at which we have already hinted. 



It is chiefly in the lizard tribe and salamander, that R lpr iuc- 

 experiments and observations on the reproduction of tiun of 

 parts have been made ; but it is reasonable, from ana- pf 

 logy, to infer, that similar phenomena may take place 

 in other tribes. The lizards are peculiarly liable, from 

 their smallnrss and the numerous enemies to which they 

 are exposed, to partial injury or destruction of their 

 member*. This is particularly the case with respect to 

 the tail, which is long and slender, and in many species 

 so brittle as to break short on being handled. I n these 



i it has been repeatedly observed, that the part 

 has been hi no long time reproduced, generally si. 



sr to the original, but sometimes a double tail has 



The reproduction of loct parts in reptile*, has been 

 made the subject of numerous and satisfactory experi- 

 ments, especially by SpsJIanisni, Bonnet, and Blunicn- 

 bach. From these it appears, that when part of either 

 extremity, or of the tail, is cut off, from two species of 

 lizard, the taceria agilit, and lacmlrit or water newt, 

 the wound i* followed, for two or three minutes, by an 

 fasten of Mood, after which the stump gradually heal*, 

 and in the course of a few day* the rudiments of a 

 new limb or tail begin to make their appearance ; that 

 these rudiment* are gradually developed, till in a few 

 r sometimes a little more than a year, there Is 

 a perfect member, similar in size and propor- 

 to that which had been cut off. only retaining for 

 time a delicacy of structure and transparency of 

 ranee not found in the original organ. It is fur- 

 proved, that those regenerated parts may be again 

 repeatedly removed and reproduced. The mot 

 Mising of thass experiments, however, are those of 

 Bonnet end Blumenbach on the reproduction of the 

 whole rye in the water newt. These have taught us, 

 that when the eye of that animal i* dissected from 

 the orbit, so a* to leave about a fifth of the membranes 

 in contact with the optic nerve, the vacant orbit is first 

 dosed by the eyelids, and gradually the vacuity is filled 

 up with a growth of new parts, which in about a year 

 acquire the perfect structure of an eye, with its invest- 

 ing membranes, contained humours, transparent cor- 

 nea, end coloured iris. 



We have already remarked the great power of ab- Tentcit _ ^ 

 stinence possssnil by reptiles, anil have now to notice uf ( . 

 some othir unfavourable circumstances under which 

 they continue to live, and perform most of their func- 



The 



of a paler colour than hi those 



in these animal*, though not so com- 



plicetn 1 a* in the higher rlaaan of animal*, t* yet a per. 

 feet circulation ; and, a* m the higher rianri. though 



Ort efl tflap MfD*F OCffTW. t h* rNOOQ taWCS 



aonw efkpaaawig uroegh the Iwig* before h be di*tri- 

 banedtothereitoftnebody. We ahall *ee. in the aoe- 

 rrr.lin ? Chapter, that although the lung, of reptile* are 

 > than theae of mmmmmlm and bmk, 

 they are lea* raaetuar, and therefore contain a amaOer 

 quantity of blood. It i, thi. >n.prrfecti.m of what haa 



the (light difrr- 

 Mood, that lay 



of the moat remarkable cnrum- 

 of tbeet animals. We are 



Most reptiles possess the faculty of residing extremes 

 of heat and cold, and the effect of chemical agents, bet- 

 ter than other animal*. Though nobody now believes 

 the ridiculous ctorie* of salamanders living in the fire, 

 it is still a curious fact, that lizards and alligators live 

 with ease, and apparent satisfaction, in the water* of hot 

 pring*, heated to a degree very considerably higher 

 than the hottest temperature of the torrid zone. Frogs 

 and newt* are often exposed to a degree of cold far be- 

 low the freezing point, while in a state of torpidity, and 

 they have even been known to remain imbedded in a 

 block of ice for many hours, without having their vi- 

 tality extinjgruitbed. Some of these animals, that have 

 been pit alive into spirit of wine, for the purpose of 

 preserving them a* specimen*, have remained alive for 



several boors; and othrr instance* are recorded of their 

 existing for a considerable time in the exhausted re. 



