286 



NATURE 



[January 17, 1901 



spoke strongly against the theory. The investigation of the 

 electrolytic tension of decomposition of the ammonium salts with 

 a mercury cathode, by Coehn and Dannenberg {Zeitschrift fur 

 anorganische Chemie, 25, 430), has given results perfectly 

 analogous to those obtained with salts of the alkali metals, a 

 result only explicable on the assumption of the ammonium 

 theory. Experiments carried out under varying conditions to 

 ascertain the possibility of reducing the heavy metals from their 

 solutions, show that the negative results previously obtained are 

 due to the great instability of the ammonium amalgam. By 

 preparing the amalgam electrolytically at low temperatures 

 (0° C), when it appears to be much more stable and does not 

 exhibit, to any great extent, the spongy appearance peculiar to 

 the amalgam prepared under ordinary conditions, and allowing 

 it to act on cold solutions of copper, cadmium and zinc salts, 

 the formation of the corresponding heavy metal amalgams is 

 easily observed. In the case of the copper, it might be possible 

 to explain the reduction by attributing it to the nascent hydrogen 

 generated in the decomposition of the ammonium amalgam ; but 

 this explanation is not possible in the case of the cadmium and 

 zinc salts. 



The additions to the Zoological Society's Gardens during the 

 past week include a Bonnet Monkey [Macacus stnicus) from 

 India, presented by Mr. R. F. Wilson ; a Polecat {Mustela 

 putorius), British, presented by Mr. Hett ; three Painted Snipe 

 {Rhyruhaea capemis) from India, presented by the Hon. Walter 

 Rothschild, M.P. ; a Tawny Owl {Syrniuin aiuco), European, 

 presented by Mr. F. Medcalf; a Deville's Tamarin {Midas 



devillii) from Peru, a Conure {Conurus ocularis), an 



Orange- winged Amazon {Chrysotis atnazonica), a Brazilian 

 Tortoise ( 7>5/«<^(? tabidata) from South America, three Japanese 

 I'heasants (Phasianus versicolor) from Japan, two Pennant's 

 Parrakeets {Platycercus elegans), a King Parrot (Aprosmicitis 

 cya,nopygius) from Australia, deposited. 



OUR ASTRONOMICAL COLUMN. 



Origin of Terrestrial Magnetism. — The Observatory 

 for January contains a translation by Prof. L. A. Bauer, of the 

 U.S. Geodetic Service, of an article in del el Terre, December 

 16, 1900, containing the results obtained by Dr. Schmidt from an 

 important harmonic analysis of the permanent magnetic field of 

 (he earth. This work has been practically an amplification of 

 Gauss' " Theorie generale du magnetisme terrestre." 



In Schmidt's analysis he does not assume the existence of an 

 interior potential function governing the entire magnetic force ; 

 but adjusting separately each of the three rectangular com- 

 ponents, obtains three expressions in place of the one determined 

 by Gauss ; moreover, the computations have been carried to the 

 terms of sixth order instead of the fourth. He concludes that the 

 magnetic force of the earth consists of three parts : — • 



(i) The greatest part, attributed to causes situated in the 

 terrestrial crust, and having a potential. 



(2) The smallest part (about one-fortieth the whole), due to 

 causes exterior to the crust, and also possessing a potential. 



(3) A part, somewhat greater than (2), not represented by a 

 potential, and therefore indicating the existence of vertical 

 terrestrial electric currents. 



Dr. Schmidt has also made careful examinations of the records 

 of magnetic storms. In that of Februaity 28, 1896, which was 

 ohyerved at fifteen observatories, and lasted from 6-7 o'clock, he 

 finds that the directions of disturbance vary considerably, at 

 times converging to a point, at others ladiating from a point ; 

 while at certain periods of comparative calm the lines of force 

 were practically parallel, suggesting a distant centre of force. 

 Taking these facts in consideration with the vertical component 

 disturbances, he concludes that the causes producing terrestrial 

 magnetic storms are for the most part exterior to the surface of 

 the earth. 



Opposition of Mars in 18S8.— Signor G. V. Schiaparelli 

 has recently published a sixth volume of observations of Mars, 

 containing the discussion of his determinations on the topo- 



graphy and constitution of the planet during the opposition of 

 1888, made with the 18-inch Mer? refractor at the Milan Ob- 

 servatory. After preliminary notes of instrumental details and 

 tables showing varying size of the disc, atmospheric'quality, &c., 

 about eighty pages are devoted to the detailed description of the 

 aspects of the many markings recognised during the period, 

 very many comparisons with the work of other observers being 

 included ; the remainder of the volume is occupied with the dis- 

 cussion of observations bearing on the constitution of the sur- 

 face, giving detailed measures and descriptions of the varying 

 polar caps, and a comparative analysis of the gemination of the 

 principal ^^ canali." Reproductions of drawings of the surface 

 markings on successive dates are included, and two polar charts 

 showing the whole of the observed phenomena in their relative 

 longitudes. 



Double Star Measures. — In the Asironotnische Nach- 

 richten (Bd. 154, No. 3679) Mr. J. Comas Sola gives a series 

 of measures of seventy-five double stars observed at Barcelona. 



SCIENTIFIC DEVELOPMENTS OF BIOLOG\ 

 AND MEDICINE. 



A N interesting monograph is just to hand in the shape of a 

 ■^*- lecture, delivered by Dr. Oscar Hertwig upon the occasion 

 of the congress of German naturalists at Aix la Chapelle (Aachen). 

 The subject is the development of biology in the nineteenth 

 century. Many interesting points, forming landmarks in the 

 progress of biological science, are discussed by the lecturer. 

 The microscope, from the inestimable service it has rendered to 

 morphology, must rank high in the discoveries of the century. 

 Before morphological method had been enriched by it, the 

 cellular hypothesis, which is the foundation stone of all biology, 

 was impossible. Dr. Hertwig accentuates the fact that progress 

 consists, not only in adding facts to our treasury of knowledge, 

 but also in stamping out error, and that some of the biological 

 energy of the nineteenth century has been consumed in annihil- 

 ating the doctrine of spontaneous generation ; it was, indeed, 

 only Pasteur's researches that established irrefutably the dictum 

 Otnne vivum e vivo, and much later still did the corollary of this, 

 namely 0/iinis celltila e cellula, firmly plant itsel.' upon biology, 

 never to be uprooted. 



A further factor of transcendental importance in the progress 

 of biology during the nineteenth century was the birth and 

 growth of the study of embryology. Its chief result was the 

 theory of evolution and the accompanying doctrines of natural 

 selection and the survival of the fittest. The lecturer enters 

 fully into the literature of this subject, which has moved the 

 biological world perhaps more than any preceding one. The 

 concluding part of the discourse is devoted to the progress made 

 in that department of biology which we know as physiology. 

 The attempt in this direction during the latter part of the 

 century has been to reduce, by means of physico-chemical 

 technique, biological phenomena to physico-chemical law. 

 This attempt, although it has given us an enormous insight into 

 the processes of life and has 'enabled us to formulate laws of the 

 highest abstract and utilitarian value, has been, in its absolute 

 sense, unsuccessful. It is doubtful if chemical and physical law 

 can ever explain fully the phenomena of life, and while physio- 

 logical chemistry and physics have destroyed the old vitalism, 

 we are, to some extent, compelled to take refuge in a new one. 

 From the practical standpoint, great progress has been made in 

 the development of pharmacology and experimental pathology. 

 The former, going hand in hand, as it ever must, with the prac- 

 tical treatment of disease, has not only thrown light upon many 

 problems of pathology and physiology, but has greatly increased 

 the possibilities of therapeutics, and given distinct hope for 

 the future in this, direction. Under experimental pathology 

 serum therapy is included, and the immense field for research 

 this has opened up. 



An address delivered by Dr. Naunyn, of Strassburg, at the same 

 congress, is of considerable interest. He chose for his subject the 

 development of medicine, hygiene and bacteriology during the 

 nineteenth century. To show the condition of medical thought 

 at the beginning of the century, he quotes from the work of 

 Prof. Kieser, of Jena, in 1812. At that time the exanthemata 

 were regarded as necessary stages in the growth of mankind, 

 and as essential to his perfect development, just as the pupa 

 stage is essential to the butterfly. The scientific development 

 of medicine, according to Prof. Naunyn, took its first real 



NO. 1629, VOL. 63 



