33^ 



NA TURE 



\Atigust II, 1 88 1 



not throw any light upon the mode of origin of that 

 group. , . . 



The chamasleons have, as we have seen, their mam 

 home in Madagascar. That island is also the main home of 

 .inother very e.xceptional group, the exceptional group of 

 l.easts called lemurs. But lemurs have much resemblance, 

 though probably no true affinity, with apes, and the apes 

 .ire a group, even more isolated perhaps than lemurs. It 

 13 as yet quite impossible to say from what root the ape 

 urder took its origin. 



The same thing may be said (and a few weeks ago was 

 said by our president in this room) respecting the ceta- 

 ceans, the order, that is, of whales and porpoises. The 

 same thing again may be said of that very exception.il 

 order of flying beasts, the bats. The chameleon family 

 then is only one of many others which have this at 

 present quite isolated character. But if we can obtain no 

 clue as to the chaniKleon's origin, can we detect any 

 special or unexpected affinities between it and any other 

 creatures which do not belong to its own class, the class 

 of reptiles ? 



It is now very generally supposed that birds have been 

 derived from reptiles, and there seem to have been two 

 distinct lines of descent — the ostrich kind of birds, from 

 extinct land reptiles called Dinosanria (of which the great 

 Iguattodon of the Wealden formation is a type) and the 

 other birds from extinct flying reptiles called Ptc-rosainia, 

 which had much analogy with our bats. This double 

 origin (which I advocated ten years ago) has recently 

 been reinforced by investigations of Prof. Vogt with 

 respect to that extinct feathered creature of the Oolite, 

 the Arclicoptcryx, which turns out to have many affinities 

 with the Pterosauria. 



Now the chamaeleon has no resemblance either to the 

 Dinosaurian or to the Pterosaurian reptiles, and certainly 

 nothing could well be less bird-like in appearance or in 

 habits than the chamalcon. The one only point of 

 resemblance — that between its pincer-like feet and those 

 of the parrots — is but a very incomplete one, as we have 

 already seen. Nevertheless there is one strange and 

 unexpected structural character already noted to which it 

 may be interesting to revert. 



In birds the lungs (unlike our own and those of beasts) 

 are not closed bags, but communicate with air-sacs which 

 extend far and wide within the body, and which doubt- 

 less facilitate their powers of aerial locomotion. In the 

 most active lizards, which dart so quickly to their shelter 

 that the eye cannot follow them, there is nothing of the 

 kind ; neither is there in those little lizards which take 

 such long jumps with the help of their parachute-like 

 wings, that they may be said to flit — lizards called by the 

 absurdly formidable name of "flying dragons ;" yet in 

 the chamasleon, in spite of its sluggishness, such sacs are 

 present, and thus render unavailing a character which 

 might otherwise be employed to distinguish all birds from 

 all existing reptiles. 



But though neither comparative anatomy nor palseon- 

 tology yet enables us to speculate profitably on the 

 origin of the chamaeleon' s family, there is one feature 

 met with in many of the species which tends to shed a 

 certain amount of light on principles of variation, and 

 therefore on that of specific origin generally. I refer to 

 the circumstance that so many kinds of chamseleons 

 develop crests, processes, or horns on the muzzle and over 

 the eyes or on the occiput. These outgrowths are so 

 different one from another that it is impossible to believe 

 that they have arisen by inheritance and descent from 

 any one peculiarity of the kind. Superciliary promi- 

 nences could not give rise to nasal protuberances, or 

 bony outgrowths to true horn-sheathed excrescences, and 

 r.ane of these could either be the parents or the offspring 

 ff occipital flips. 



The phenomenon is parallel to what we find in certain 

 groups of birds, as e.g., the birds of paradise, so many 



kinds of which develop unusual feathery outgrowths — 

 these outgrowths being often so different in nature that 

 they cannot be supposed to have been derived by in- 

 heritance one from another. 



In such birds then we must admit (as I have long ago 

 urged) that there exists an innate tendency to unusual 

 outgrowths of feathers of one or another kind, and 

 similarly we must admit that there is extant in the nature 

 or essence of chamaeleons a tendency to osseous or horny 

 outgrowths from the head of one or of another kind. It 

 has been suggested that these outgrowths in the males 

 are due to the wayvv'ard fancy of female chamaleon taste. 

 And certainly the female chamaeleon, with her excep- 

 tional power of independently moving her eyes, and so 

 simultaneously considering and accurately comparing the 

 horns and warts of two rival swains, is unusually quali- 

 fied for making a careful matrimonial choice. Seriously 

 speaking, however, I regard this explanation as quite 

 inadequate. 



I have elsewhere ' given my reasons for considering 

 this explanation to be a mistaken one, but the question is 

 far too wide to discuss to-day, suffice it to say that even 

 if this hypothesis \vere correct it would but imply the 

 presence of an innate tendency in the female to admire 

 horny and warty prominences of certain varied kinds. 

 The one innate tendency is as mysterious, and when 

 deeply considered as significant as in the other. 



But apart from these questions, which, however inter- 

 esting they may be, are still matters of uncertain specula- 

 tion, the actual structure and the unquestionable facts of 

 the chama:leon's physiology are, as I trust you will now 

 agree with me in saying, matters of very great interest. 

 They offer fields as yet unexplored for careful observa- 

 tion and experiment. Even the most peculiar and im- 

 portant of all the chamffileon's actions — the emission and 

 retraction of its tongue — are actions which, so far as I 

 know, are not by any means clearly understood. But 

 when to such matters of direct observation or immediate 

 inference we add the problems to the solution of which 

 elaborate reasoning has to be employed — reasoning based 

 on wide knowledge of the structures of animals existing 

 and extinct — it will, I think, be evident that the leisure of 

 a long life might be usefully devoted to obtaining a com- 

 plete and far-reaching knowledge of the natural history of 

 that exceptional family of Lacertian reptiles, the family of 

 the chameleons. 



THE INTERNATIONAL MEDICAL CONGRESS 

 'X'HE seventh meeting of the International Medical 

 -'■ Congress, which has just been held in London, 

 has been remarkable from many points of view. The 

 sudden growth of the Congress from an assembly of 

 6oo to one of over 3000 members, the truly cosmo- 

 politan character of the gathering, the great scientific 

 activity displayed, the lavish private and public hos- 

 pitality and marked Royal patronage conferred, have one 

 and all marked out this meeting as a very great event. 

 It has been the largest and most complete assembly of 

 scientific men that this age, and therefore any age, has 

 ever witnessed, and if the results to science should prove 

 to be at all commensurate, it will be a very prominent 

 event in the history of the progress of science. 



The many and complicated arrangements have been 

 admirably planned by Mr. MacCormac and his able 

 assistant, Mr. Makins, and they have borne successfully 

 the heavy strain of a larger number of members than was 

 previously expected. The Congress has held six general 

 meetings, at each of which an address has been delivered, 

 and the more special work has been conducted in the 

 fifteen sections among which it has been split up. Sir 

 James Paget, as President, delivered the opening address 

 on Wednesday last, which was characterised by his usual 



' " Lessons from Nature," Chap. X. (Murray, 1876). 



