148 



X.-d TURE 



[June 13. 1S95 



LETTERS TO THE EDITOR. 



[ The Editor does not hold himself responsible for opinions ex- 

 pressed by his iorrespoitdents. Neither can he undertake 

 to return^ or to correspond luith the writers of, rejected 

 manuscripts intended for this or any other part of NATURE. 

 Ac notice is taken of anonymous communications.^ 



Hypnotised Lizards. 



Several communications relating to the .so-called " death- 

 feigning instinct " of certain reptiles have appeared in the 

 columns of Nature during the last few months. The following 

 obsenations bearing on this question may be of sufficient interest 

 to justify publication. They refer to a sjwcies of lizard of the 

 genus Stellio (identified in Tristram's "Fauna and Flora of 

 Palestine" as S. cordylina), which is extremely common in these 

 parts. When one of these lizards is captured, it makes a few 

 vigorous efforts to escape, and then, if held firmly, falls into a 

 limp, motionless state, which might easily lead an inexperienced 

 person to think it dead. A very little examination, however, 

 shows that the animal is not dead, but in a trance-like conditiim. 

 Gentle respiratory movements are visible just behind the 

 shoulders, and sometimes show a rising and falling rhythm with 

 short intervals of complete rest ; the eyes may remain wide open, 

 but are commonly half-closed, and the lids wink slowly Irom 

 time to time spontaneously or by reflex action ; the mouth is 

 almost always open — sometimes wide, sometimes but little — and 

 in either case the jaw is quite rigid, and if closed by force is apt 

 to reopen when the pressure is withdrawn ; the limbs lie extended 

 and semi-flaccid, with some approach to a cataleptic condition, 

 i.e. if bent, or stretched into positions not too strained, they 

 maintain such jwsilions when let go ; and the same is true of 

 the trunk and tail. If, now, the lizard be laid down gently nn 

 the floor or on a table, it will lie perfectly still and seemingly 

 unconscious for some minutes (unless roused by a sudden jar or 

 loud noise), the eyes preserving throughout a peculiarly vacant, 

 expres.sionless as|)ect, quite suggestive of death. While in this 

 state the lizard may be put into a variety of positions without 

 eliciting any sign of consciousness, and will lie .is quietly on its 

 hack as in the natural position ; and I have without difticulty 

 made one maintain various grotesque [x)stures, such as .standing 

 erect with one hand resting on the edge of a Ixjok, like a preacher 

 t)chind a pulpit ; bending sharply around, and seizing the tail 

 with the claws of one fore-foot ; cocking the tail over the back, 

 scorpion fashion, &c. 



.Although some reflex actions .ire maintained (<-.^. winking, as 

 above mentioned), there is a considerable degree of cutaneous 

 anasthesia. as shown by the fact that a pin may be run through 

 a fold of skin without fully rousing the animal, a sluggish, feeble 

 wriggle txring the .sole result. 



This trance slate (obviously akin lo.some phases of hypnotism) 

 lasts, as before stated, for sever.il minutes. I have on several 

 occasions timed it, the li/.ard being laid on its l)ack, and myself 

 concealed or standing quite still at a distance, and in each 

 instance recovery seemed to come suddenly after alx>ut five 

 minutes (sometimes a few seconds less, sometimes more), the 

 animal .showing no sign of consciousness until by one brusque 

 effort it turned over into the normal [wsition ; this done, it lies 

 quite still, but evidently awake and observant, for a few moments 

 more, and then .scuttles off in a hurry. 



I find that the reailiest way of inducing the trance is to take 

 the liz^ard's hcail between my finger and thumb, making gentle 

 pressure upon the angles of the jaw and u|Mjn the tympanic 

 mendirane.s ; but similar pressure on the sides of the trunk, just 

 behind the forelimbs, is just alMiut as cffc:tive. 



.Such are the facts: anti it seems to me that, so far as the 

 animal in question is concerned, they lend no supixirl whatever 

 to the hyp<jtliesis of voluntary or conscious dealh-leigning ; but, 

 on the contrary, are fx.Tfectly consistent with the view that .such 

 ph'-norn'im Ijelong to the same cla.ss iis the various manifestations 

 II, iVc, with which wc arc all more or less familiar 

 ;■ n subiecl. 



' . for the sake of argument, that we have to 



-linn, and not, as I believe, with a mere 



1 1 reaction of the higher nervous centres — 



what poMible purpr)sc coulil such an instinct serve ? The 



natural enemies ol these liziirds are foxes, jackals, martens, 



'or U of prey, and snakes. Can any one believe that any one ol 



1 • animals, having captured a lizard, would be in the lca.st 



NO. 1337, VOL. 52] 



inclined to let it go because it lay motionless and apparently 

 I dead in the captor's grasp ? Or will it be argued that the trance 

 I condition is a Sjwcial gift " in mercy" to the victim, to mitigate 

 or abolish the pain of death? If the last be the true explana 

 tion, one is tempted to ask « hy such tenderness is shown to a 

 favoured few of the victims in nature's wondrous system, while 

 the m.ijority (pace Dr. .\. R. Wallace) are left in ))ossession of 

 consciousness and sensibility more or less acute until they have 

 sustained enough mechanical injury to kill or stun them. 



W. T. Van Dyck. 

 Beyroul, Syria, May i6. 



Stridulating Organ in a Spider. 



It is exactly twenty yuars now since I described to Geoffry 

 Nevill the sound made by our large " BhaUik -Mokra " (or Bear 

 Spider). I noticed that Wood Mason, who sat opposite me, 

 appeared to be highly amused, but he said nothing. 



Next morning when he joined Nevill and me at table, Mason 

 was in high glee, and said, " I've found out all aliout your 

 wonderful sjiider. I thought yesterday you were telling 

 Nevill a stiff yarn for anuisement, but as it wasn't your usual 

 custom, I unbottled a lot of the big spitlers, antl found the 

 stridulating apparatus.'' 



He there and then made me recite all over again, and promise 

 to write out, what he quoted in the I'rans. Ent. Soc, 1877, and 

 give him a sketch, which is plate vii. ; a [jrevious notice of it all 

 appearing in our Proc. As. Soc, Bengal, 1876, and .-/««. and 

 Mag. A'al. Hist. 



It was in the cold sea.son of 1869-70 that 1 captured the speci- 

 men, and noticed the stridulating phenomena. The sound can 

 be heard easily at ten or twelve yards, antl is like pouring small 

 shot on a plate. 



I should not have mentioned the above, were it not that my 

 report of " sound-producing .Vnts" seems to have been over- 

 looked. If I mistake not. Sir John Lubbock looks on them as 

 a silent group ; but it is ten or twelve years now since I drew 

 attention to the sounds made, and gave a .small " Morse" dia- 

 gram of the same, either in Nature or the English Mechanic, 

 one kind of ant giving a .series of triple sounds, another kind a 

 set of five or six, gradually decrexsing. 



I describeil how the soimds were made by rasping the horny 

 tip of the la.st abdominal segment on any resonant material, such 

 as thin dry bark, dry leaves, &c. 



Iain not aware if the tolerably loud jiercussive "tok-tok" 

 of the Mahsir (liarhestMacrocep) is known. I described it to a 

 friend in l'"ngland in 1879, and saw it quoted in the Daily 

 Telegraph (about .August to October) soon after. 



While on this subject, I may mention that we have a rather 

 rare butterfly here, which is dark in colour, some three inches 

 across, a very hard flyer, and when darting about (generally after 

 sunset), in a shady avenue, makes a scries of taps, sounding like 

 " lip, tip, tip." 



Three or four of these butterflies generally fly together. I 

 have not seen one alone ; and though I have often enough tried 

 to catch one, never .secured a specimen. The sound, 1 presume, 

 is made by striking the anterior margins of wings together : 

 and if .standing still, one can hear the "tip. tip'' six or seven 

 yards off. 



There are, no doubt, many things of this sort that an old 

 "Jungli walla" woulil know, and think of small value, I havi 

 been surprised at the little often known about the habits and 

 appearance of many aninuils and insects. Not three years ago. 



a well-known naturalist was quile interested in my (hvcription 

 of the " happy family" one often finds in the holes, a hlJe above 

 water level, in our clay banks of small ri\ers, at low water 

 iluring cold .sea.son ; fish of several kinds, and crabs (three and 

 four inches across) living together in the hole umler water as a 

 " colony." Hut for these tolerably deep holes, the oilers would 

 leave no fish in the smaller rivers. 



S. E. I'liAl.. 

 Sibsagar, A.sam, May 9. 



