Sept. I, 1881] 



NATURE 



405 



unwary insect alights on them. The plant, in fact, actually 

 captures and devours insects. This observation also reniair,ed 

 as an isolated fact until within the last few years, when Darwin, 

 Hooker, and others have shown that many other species have 

 curious and very varied coutrivarces for supplying themselves 

 with animal food. 



Son, e of the most fascinating branches of botany — morihology, 

 histology, and physiology — scarcely existed before 1830. In the 

 two former branches the discoveries of von Mohl are pre-en.inent. 

 He first observed cell-division in 1S35, and detected the presence 

 of starch in chlorophyll-corpuscles in 1837, while he first de- 

 scribed protojilasm, now so familiar to us, at least by name, in 

 1846. In the fame year Amici discovered the eNi^tence of the 

 embryonic vesicle in the embryo sac, which c'evelops into the 

 embryo when fertilised by I he entrance of the pollen-tube into 

 the niicropyle. The existence of sexual reproduction in the 

 lower plants w as doubtful, or at least doubted by seme eminent 

 authoiiiies, as recently as 1S53, when the actual process of 

 fertilisation in the c mmon bladderw rack of our shores was 

 observed by Thuret, while the reproduction of the larger fungi 

 was first worked out by De Bary in 1863. 



As regards lichens, Schwendener proposed, in 1869, the 

 startling theory, now however accepted by some of the highest 

 authorities, that lichens are not autoncmous organisms, but 

 commensal associations of a fungus parasitic on an alga. With 

 reference to the higher Cryptogams it is hardly too much to say 

 that the whole of cur exact knowledge of their life-history has 

 been obtained during the last half-century. Thus in the case of 

 ferns the male organs, or antheridia, were first discovered by 

 Nageli in 1S44, and the archegonia, or female organs, by 

 Suminsli in 1S4S. The early s'ages in the development of 

 mosses were worked out by Valentine in 1833. Lastly, the 

 principle of Alternation of Generations in plants was discovered 

 by Hofuieister. This eminent naturalist also, in 1851-4, 

 pointed out the homologies of the reproductive processes in 

 mosses, vascular cryptogams, gymnosperms, and angiosperms. 



Nothing could have appeared less likely than that researches 

 into the theory of spontaneous generatic n shr uld have led to 

 practical imj rovements in medical science. Yet such has been 

 the case. Only a few years ago Bacteria seemed mere scientific 

 curiosities. It had long been l%nown that an infusion — say, of 

 hay — would, if exposed to the atmosphere, be foimd, after a 

 certain time, to teem with living forms. Even those few who 

 still believe that life w ould be spotanecusly generated in such an 

 infusion, will admit that these minute organisms are, if not 

 entirely, yet mair.ly, derived frcm germs floating in our atmo- 

 sphere ; and if precautions are taken to exclude such germs, as 

 in the careful experiments especially c f Pasteur, Tyndall, and 

 Roberts, every one w'ill grant that in ninety-nine cases out of a 

 hundred no such development of life will take place. 



These facts have led to most important results in Surgery. 

 One rerson why compound fractures are so dangerous, is because, 

 the skin being broken, the air obtains access to the wound, 

 bringing with it innumerable germs, which too often set up 

 putrefyirg action. Lister first made a practical application of 

 these observations. He set himself to find some substance 

 capable of killing the germs, v ithcut being itself too potent a 

 caustic, and he found that dilute carbclic acid fulfilled these 

 conditions. This discovery has enabled many operations to be 

 performed which would previously have been almost hopeless. 



The same idea seems destined to prove as useful in Medicine 

 as in Surgery. There is great reason to suppose that many 

 disease^, especially those of a zymotic character, have their 

 origin in the germs of special organism---. We know that fevers 

 run a certain definite course. The parasitic organisms are at 

 first few, but gradually n ultiply at the expense of the patient, 

 and then die out again. Indeed, it seems to be thoroughly 

 eslablished that many diseases are due to the excessive multipli- 

 cation of microscopic organisms, and we are not without hope 

 that means will be discovered by which, without injury to the 

 patient, these terrible, though minute, enemies may be destroyed, 

 and the disease thus stayed. The interesting researches of 

 Burdon Sanderson, Greenfield, Koch, Pasteiw, Toussaint, and 

 others, seem to justify the hope that we may be able to modify 

 these and otter germs, and then by appropriate inoculation to 

 protect ourselves against fever and other acute diseases. 



The history of Anaesthetics is a most remarkable illustration 

 of how long we may he on the very verge of a most important 

 discovery. Ether, which, as we all know, produces perfect 

 insensibility to pain, was discovered as long ago as 1540. The 



anaesthetic property of nitrous oxide, now so extensively used, 

 was obsen-ed in 1800 by Sir II. Davy, who actually experi- 

 mented on himself, and had one of his teeth painlessly extracted 

 when under its influence. He even suggests that "as nitrous 

 oxide gas seems capable of destroying pain, it could probably 

 be used with advantage in surgical operations." Nay, this 

 properly of nitrous oxide was habitually explained and illustrated 

 in the chemical lectures given in hospitals, and yet for fifty years 

 the gas was never used in actual operations. 



Few branches of science have made more rapid progress in 

 the last half-century than that w hich deals with the ancient con- 

 dition of nan. When our Association was founded it was 

 generally considered that the human race suddenly appeared on 

 the scene, about 6coo years ago, after the disnppearance of the 

 extinct mammalia, and when Europe, both as regards physical 

 conditions and the other animals by which it was inhabited, was 

 pretty much in the same condition as in the period covered by 

 Greek and Roman history. Since then the persevering re-earches 

 of Layard, Kawlinson, Botta and others have made known to us, 

 not only the statues and palaces of the ancient Assyrian monarchs, 

 but even their libraries ; the cuneiform characters have been 

 deciphered, and we can not only see, but read in the British 

 Museum, the actual contemporary records, on burnt clay cylin- 

 ders, of the events recorded in the historical books of the Old 

 Testament and in the pages of Herodotus. The researches in 

 Egypt also seem to have satisfactorily established the fact that 

 the pyramids themselves are at least 6cco years old, while it 

 is obvious that the Assyrian and Etiyptian monarchies cannot 

 suddenly have attained to the wealth and power, the state of 

 social crganisation, and progress in the arts, of which we have 

 before us, preserved by the sand of the desert fi-om the ravages 

 of man, such wcnderful j^roofs. 



In Europe, the writings of the earliest historians and poets 

 indicated that, before iron came into general use, there was a 

 time when bronze was the ordinary material of weapons, axes, 

 and other cutting implements, and though it seemed <i priori 

 improbable that a comi.iouncl of copper and tin should have 

 preceded the simple metal iron, nevertheless the researches of 

 archaeologists have shown that there really was in Europe a 

 "Bronze Age," which at the dawn of history was just giving 

 way to that of " Iron." 



The contents of ancient graves, buried in many cas es so that 

 their owner might carry some at least of his wealth with him to 

 the world of spirits, left no room for doubt as to the existence of 

 a Bronze Age ; bat we get a completer idea of the condition of 

 Man at this period from the Swi s lake-villages, first ma<le known 

 to us by Keller. Along the shallow edges of the Swi.ss lakes 

 there flourished, once upon a time, many popukus villages or 

 towns, built tin platforms supported by piles, exactly as many 

 Malayan villages are now. Under these circumstances innu- 

 merable objects were one by one dropjied into 'he water ; some- 

 times whole villages were burnt, and their contents submerged ; 

 and thus we have been able to recover, from the w'aters of 

 oblivion in which they had rested for more than 20CO years, not 

 only the arms and tools of this a- cient people, the bones of their 

 animals, their potteiy and ornaments, but the stuffs they wore, the 

 grain they had stored up for future use, even fruits and cakes 

 of bread . 



But this bronze-using people were not the earliest occupants'of 

 Europe. The contents of ancient tombs give evidence of a time 

 when metal was unknown. This also was confirmed by the 

 evidence then unexpectedly received from the Swiss lakes. By 

 the side of the bronze-age villages were others, not less extensive, 

 in which, while implements of stone and bone were discovered 

 literally by thousands, not a trace of metal was met with. The 

 shell-mounds or refuse-heaps accumulated by the ancient fisher- 

 men ah ng the shores of Dennark, fully confirmed the existence 

 of a " Stone Age." 



No bones of the reindeer, no fragment of any of the extinct 

 mammalia, have been found in any of the Swiss lake-villages or 

 in any of the thousands of tumuli which have 1 een opened in our 

 own country or in Central and Southern Europe. Yet the contents 

 of caves and of river-gravels affcrd abundant evidence that there 

 was a time when the mammoth and rhinoceros, the mu-k-ox and 

 reindeer, the cave lion and hyena, the gieat bear and the gigantic 

 Irish elk wandered in our woods and valleys, and the hippopo- 

 tamus floated in our rivers; when England and France were 

 united, and the Thames and the Rhine had a common estuary. 

 This was long supposed to be before the advent of Man. At 

 length, however, the discoveries of Boucher de Perthes in the 



