CHEMISTRY. 



101 



atoms, and J. J. Thomson has shown that this 

 breaking up of the molecule can be effected 

 by heat-vibrations, and by the electrical dis- 

 charge at a comparatively low temperature. 

 But none of our present atoms have been as 

 yet split up. The spectrum has been thought 

 at times to indicate something of the kind, but 

 the phenomena so regarded may be more ra- 

 tionally referred to the presence of impurities 

 or defect of observational power. So that 

 neither the earth nor the stars have as yet given 

 any evidence of a resolution of any element. 

 Crookes has, however, added a remarkable con- 

 tribution to the question of the possibility of 

 decomposing the elements, in his observations 

 of the peculiar and characteristic lines in the 

 phosphorescent lights emitted by certain chemi- 

 cal compounds, especially the rare earths, 

 under an electric discharge in a high vacuum ; 

 but the explanation of these phenomena does 

 not necessitate atomic decomposition. Ther- 

 mal chemistry is even yet in its infancy, but 

 " an infant of sturdy growth, likely to do good 

 in the world " ; while great advance is prom- 

 ised in the region of electrical chemistry. By 

 the theory of the constitution of matter by 

 molecular arrangement, we are able not only 

 to explain the differences in isomeric sub- 

 stances, but also to predict the number of dis- 

 tinct variations in which any given chemical 

 compound can possibly exist. "This power 

 of successful prediction constitutes a high- 

 water mark of science, for it indicates that the 

 theory upon which such a power is based is a 

 true one." With this doctrine, associated with 

 that of valency, organic chemistry has be- 

 come synthetic, and Liebig and Wohler's pre- 

 diction fifty years ago, that sugar, morphia, 

 and salicene would be artificially prepared, has 

 been fulfilled. With the success achieved in 

 this line of experimentation, " the belief in a 

 special vital force has disappeared like an ignis 

 fatum, and no longer leads us in the wrong 

 direction. We know now that the same laws 

 regulate the formation of chemical com- 

 pounds in both animate and inanimate Nature; 

 and the chemist only asks for a knowledge of 

 the constitution of any definite chemical com- 

 pound found in the organic world, in order to 

 be able to promise to prepare it artificially." 

 Yet the barrier which exists between the or- 

 ganized and unorganized worlds is one which 

 the chemist at present sees no chance of break- 

 ing down. "Protoplasm, with which the sim- 

 plest manifestations of life are associated, is not 

 a compound but a structure built up of com- 

 pounds. The chemist may successfully syn- 

 thetize any of its component molecules, but he 

 has no more reason to look forward to the 

 synthetic production of the structure than to 

 imagine that the synthesis of gallic acid leads 

 to the artificial production of gall-nuts." Lie- 

 big's classification of food-substances into those 

 which serve for maintaining the heat of the 

 body and those which are needed for repair- 

 ing muscular waste, has not held good. The 



nitrogenous constituents of food do doubtless 

 go to repair the waste of muscle, while the 

 function of the non-nitrogenous food is not 

 only to supply the animal heat, but also to 

 furnish, by its oxidation, the muscular energy 

 of the body. We thus come to the conclusion 

 that it is the potential energy of the food which 

 furnishes the actual energy of the body, ex- 

 pressed in terms either of heat or of mechan- 

 ical work; and to this must be added the ac- 

 tion of the mind or the body not yet accounted 

 for. Liebig's assumption that plants derive 

 their carbon mainly from the atmosphere 

 rather than from the ground, has been con- 

 firmed by the forty-four years' experiments of 

 Lawes and Gilbert ; but his theory that the 

 whole of the nitrogen required by the plant is 

 derived from atmospheric ammonia, is shown 

 by the same experiments to be inadequate. 

 Some light is given upon the origin of this 

 nitrogen by Berthelot, who has shown that 

 under certain conditions the soil has the power 

 of absorbing the nitrogen of the air and form- 

 ing compounds which can subsequently be as- 

 similated by the plant. The microscope has 

 contributed to our knowledge of fermentative 

 processes by showing, in contradiction of Lie- 

 big's purely chemical view, that they are pro- 

 duced by the growth of new organisms ; but 

 chemistry steps in again at this point with the 

 discovery that these organisms act by develop- 

 ing definite chemical compounds, the nature 

 of which, and their function in provoking dis- 

 ease, it is for that science to determine. 



Investigations of the spectra of various rare 

 earths have led Mr. William Crookes to declare 

 that there are elements, the existence of which 

 is revealed by the spectrum lines, but which 

 still remain to be separated. This view is con- 

 firmed by his own fractional separation of the 

 earths of yttrium and by the parallel re- 

 searches of Dr. Auer von Welsbach, M. de 

 Boisbaudran, and M. Demarcay. Under these 

 researches, yttrium indicated that it was com- 

 posed of five constituents, and the two ele- 

 ments into which the didymium had been 

 separated appeared each to consist of several. 

 Other researches, by l)rs. Krtiss and Nilson, 

 upon rare earths in Scandinavian minerals, 

 have yielded still more interesting results, 

 the main outcome of which appears to be that, 

 instead of holmium, erbium, thulium, didym- 

 ium, and samarium, we must, if we follow 

 these authors, recognize the existence of at 

 least twenty-two new elements. If we add 

 to these the results previously obtained by Mr. 

 Crookes with respect to yttrium, instead of 

 six, we shall find ourselves in the presence of 

 twenty-seven elements, and realize a gain of at 

 least twenty-one such bodies. 



Dr. T. Sterry Hunt proposes a new theory 

 of the process of chemical union or combina- 

 tion, which he defines as integration. It may 

 take place either among unlike or like species, 

 and is in the latter case a homogeneous inte- 

 gration, constituting what is called polymeriza- 



