December 13, 1889.] 



SCIENCE. 



399 



undiscovered element has attracted to it the attention of the whole 

 scientific world. 



The once permanent gases are permanent no more. Dulong 

 and Petit's law has found a complement in the methods of Raoult. 

 The old doctrine of valency is giving way to more elastic hypoth- 

 eses. The extraordinary progress of organic chemistry, which 

 originated in the work and influence of Liebig and the Giessen 

 school, has continued at an accelerated rate. The practical value 

 of even the most recondite investigations of pure science has again 

 been exemplified by the enormous development of the coal-tar in- 

 dustry, and by the numerous syntheses of organic products which 

 have added to the material resources of the community. 



The increase of our knowledge of the sun by means of localized 

 spectroscopic observation, the application of photography to astron- 

 omy, and, more recently still, the extension and generalization of 

 the nebular hypothesis, are perhaps the most remarkable develop- 

 ijients of those branches of science which relate to astronomy. 

 Stars which no human eye will ever see are now known to us as 

 surely as those which are clearly visible. The efforts to reduce 

 nebulse, comets, and stars under one common law, as various cases 

 of the collision or aggregation of meteoritic swarms, and the strik- 

 ing investigations of Professor Darwin on the effects of tidal action 

 and on the application of the laws of gases to a meteoritic plenum, 

 give promise of a fuller knowledge of the birth and death of 

 worlds. 



In the biological sciences, the progress during the last twenty 

 years has consisted chiefly in the firm establishment of the Dar- 

 winian doctrine, and the application of it and its subordinate con- 

 ceptions in a variety of fields of investigation. The progress of 

 experimental physiology has been marked by increasing exactitude 

 in the application of physical methods to the study of the proper- 

 ties of living bodies ; but it has not as yet benefited, as have other 

 branches of biology, from the fecundating influence of Darwin's 

 writings : hence there is no very prominent physiological discovery 

 to be recoided. The generation of scientific men which is now 

 coming to middle age has been brought up in familiarity with Mr. 

 Darwin's teaching, and is not affected by any thing like hostility or 

 ffl/rz'orz' antagonism to such views. The result is seen in the vast 

 number of embryological researches (stimulated by the theory that 

 the development of the individual is an epitome of the development 

 of the race) which these twenty years have produced, and in the 

 daily increasing attention to that study of the organism as a living 

 thing definitely related to its conditions which Darwin himself set 

 on foot. The marine laboratories of Naples, Newport, Beaufort, 

 and Plymouth, have come into existence (as in earlier years their 

 forerunners on the coast of France), and served to organize and 

 facilitate the study of living plants and animals. The " Challenger " 

 and other deep-sea exploring expeditions have sailed forth and re- 

 turned with their booty, which has been described with a detail and 

 precision unknown in former times. The precise methods of 

 microscopic study by means of section-cutting — due originally to 

 Strieker of Vienna — have within these twenty years made the 

 study of cell-structure and cell-activity as essential a part of mor- 

 phology as it had already become of physiology. These, and the 

 frank adoption of the theory of descent, have swept away old ideas 

 of classification and affinities, and have relegated the ascidian 

 " polyps " of old days to the group of Vertebra/a, and the sponges 

 to the coelenterates. The nucleus of the protoplasmic cell — which 

 twenty years ago had fallen from the high position of importance 

 accorded to it by Schwann — has, through the researches of 

 Bijtschli, Flemming, and Van Beneden, been reinstated, and is now 

 shown to be the seat of all-imporlant activities in connection with 

 cell-division and the fertilization of the egg. The discovery of the 

 phenomena of karj'okinesis and their relation to fertilization will be 

 reckoned hereafter as one of the most, if not the most, important 

 of the biological discoveries of the past twenty years. 



Apart from Darwinism, the most remarkable development of 

 biological studies during these " twice ten tedious years " is un- 

 doubtedly the sudden rise and gigantic progress of our knowledge 

 of the bacteria. Though the foundations were laid fifty years ago 

 by Schwann and Henle, and great advances were made by Pasteur 

 and by Lister just before our period, yet it is within this span that 

 the microscope and precise methods of culture have been applied 



to the study of the " vibrions," or " microbes," and the so-called 

 " bacteriology " established. We now know, through the labors 

 of Toussaint, Chauveau, Pasteur, and Koch, of a number of dis- 

 eases which are definitely caused by bacteria. We also have 

 learned from Pasteur how to control the attack of some of these 

 dangerous parasites. Within these twenty years the antiseptic 

 surgery founded by Sir Joseph Lister has received its full measure 

 of trial and confirmation, while his opportunities and those of his 

 fellow-countrymen for making further discovery of a like kind have 

 been ignorantly destroyed by an act of Parliament. 



To particularize some of the more striking zoological discoveries 

 which come within our twenty years, we may cite the dipnoous 

 fish-like creature Ceratodus of the Queensland rivers, discovered 

 by Krefft ; the jumping wheel-animalcule Pcdalion, of Hudson ; 

 the development and the anatomy of the archaic arthropod Perip- 

 atus worked out by Moseley, Balfour, and Sedgwick ; the Hydro- 

 corallina of Moseley, an entirely new group of compound animals ; 

 the fresh-water jelly-fish Limnocodium of the Regent's Park lily- 

 tank ; the Silurian scorpion of Gotland and Lanarkshire ; the pro- 

 tozoon Chlamydomyxa discovered by Archer in the Irish bogs ; 

 the Odoniornithes and the Dinocerata of the American paleontolo- 

 gists ; the intracellular digestion obtaining in animals higher than 

 Pri7i'o5'oa, and the significance of the "diapedesis" of blood-cor- 

 puscles in inflammation, and the general theory of phagocytes due 

 to Mecznikow ; the establishment of the principle of degeneration 

 as of equal generality with that of progressive development, by 

 Anton Dohrn ; the demonstration by Weismann and others that 

 we have no right to mix our Darwinism with Lamarckism, since 

 no one has been able to bring forward a single case of the trans- 

 mission of acquired characters. Perhaps the attempt to purify the 

 Darwinian doctrine from Lamarckian assumption will hereafter be 

 regarded, whether it be successful or not, as the most characteris- 

 tic feature of biological movement at the end of our double decade. 

 Its earlier portion was distinguished by the publication of some of 

 Darwin's later works. Its greatest event was his death. 



In botany, twenty years ago, the teaching in our universities was 

 practically sterile. In one of our earliest numbers. Professor James 

 Stewart defended with some vigor the propriety of intrusting botany 

 to a lecturer at Cambridge who was also charged with the duty of 

 lecturing on electricity and magnetism. It is startling to compare 

 a past, in which botany was regarded as a subject which might be 

 tacked on anywhere, with its present condition, in which there is 

 scarcely a seat of learning in the three kingdoms which is not 

 turning out serious work. The younger English school would be 

 ungrateful if it did not acknowledge its debt to the eminent Ger- 

 man teachers from whom it has derived so much in the tradition 

 and method of investigation. Sachs and De Bary have left an 

 indelible mark on our younger professors. But it would be a mis- 

 take to suppose that English modern botany has simply derived 

 from Germany. It has developed a character of its own, in which 

 the indirect influence of Darwin's later work can be not indistinctly 

 traced. There has been agradual revolt in England, the ultimate con- 

 sequences of which have still to be developed, against the too physi- 

 cal conception of the phenomena of plant-life which has been preva- 

 lent on the Continent. Darwin, by his researches on insectivorous 

 plants and plant movements from a purely biological point of view, 

 prepared the way for this ; Gardiner followed with a masterly dem- 

 onstration of the physical continuity of protoplasm in plant-tissues. 

 This has thrown a new light on the phenomena studied by Dar- 

 win ; and we need not, therefore, be surprised that his son, F. 

 Darwin, has started what is virtually a new conception of the pro- 

 cess of growth, by showing that its controlling element is to be 

 sought in the living protoplasm of the cell rather than in the in- 

 vesting cell-wall. On the whole, English botanists have shown a 

 marked disposition to see in the study of protoplasm the real key 

 to the interpretation of the phenomena of plant-life. The complete 

 analogy between the processes of secretion in animals and vege- 

 tables established by Gardiner, and the essential part played by fer- 

 ments in vegetable nutrition, illustrated by Green, are examples of 

 the results of this line of inquiry. To Germany we owe a flood of 

 information as to the function of the cell-nucleus, which, it is 

 singular, has met with general acceptance but little detailed cor- 

 roboration in this country. 



