April 26, 1906] 



NA TURE 



619 



complex these structures, the more convincing the evidence 

 they furnish, since it then becomes so much the less prob- 

 able that the same anatomical device should have been 

 produced twice than that it should have been acquired once 

 only. In the Artiodactyla, for example, " a definite case 

 of an anatomical peculiarity, so well marked and complex 

 as to be a safe guide to affinity," is seen in the elongation 

 and spiral coiling of the proximal portion of the colon. 

 The Perissodactyla and rodents supply other examples of 

 evolution along a definite radius from the ancestral centre. 

 From his investigations the author deduces inferences of 

 importance for the general theory of evolution, especially 

 as regards the limitation of the possible range of variation 

 of organs in any set of animals which have once come to 

 occupy a particular radius. Further changes and elabor- 

 ations are then restricted by the past history, that is to 

 say, by the limited material which it has furnished for 

 further specialisation. In this way a simple explanation 

 is given for the definite grooves, recognised by many 

 writers, along which the specialisation of organisms must 

 necessarily move, without having recourse to the assump- 

 tion of any mysterious directive forces. E. A. M. 



SCIENTIFIC REPORTS OF THE LOCAL 

 GOVERNMENT BOARD. 1 

 ""THE first half of the volume under notice is devoted to 

 the medical officer's report, statistical data, and de- 

 tails of various inspections and inquiries by the Board's 

 inspectors. The second half contains reports of the 

 auxiliary scientific investigations carried out for the Board. 

 The first of these is a memorandum by Dr. Theodore 

 Thomson on rats and ship-borne plague. The conclusion 

 arrived at is that " the part played by ihe rat in trans- 

 mission of plague to man, although real, falls far short 

 of the importance which has generally been attributed to 

 it." This may be true, but in view of the predominant 

 part played by the rat in the dissemination of plague in 

 the various Sydney epidemics, it is to be hoped that the 

 campaign against this rodent will in no way be relaxed. 



Bearing on the same subject, Drs. Haldane and Wade 

 report on methods of rat destruction and disinfection on 

 ship-board. In this especial attention is directed to the 

 Clayton process, in which sulphur is burned at a high 

 temperature, and air charged with the products of its 

 combustion is pumped into the ship's hold. The gas is 

 rapidly fatal to rats and other vermin, and is germicidal 

 to non-sporing microbes, but it does not penetrate a loaded 

 hold well, and has a deleterious action on certain articles. 

 On the whole, however, it seems to be the best method to 

 employ for rat destruction. Dr. Klein details further ex- 

 periments on the two types, virulent human and less 

 virulent rat, of the plague bacillus differentiated by Rim 

 and described in a previous report. Dr. Klein also 

 records some interesting observations on the influence of 

 symbiosis on the virulence of microbes. 



An important paper on the differentiation of various 

 streptococci and staphylococci is contributed by Dr. M. H. 

 Gordon. Hitherto the differences exhibited by the members 

 of these classes of micro-organisms, particularly the 

 streptococci, have been slight and indefinite, but by making 

 use of culture media containing various mono-, di-, tri-, 

 and pply-saccharides and glucosides, important differential 

 characters are obtainable. Dr. Sidney Martin has con- 

 tinued his studies on the toxic action of microbes, dealing 

 in the present volume with that of the Proteus vulgaris. 

 The results, however, in this case are somewhat indefinite, 

 the toxic reaction being mainly evinced by the develop- 

 ment of agglutinin in the blood. Dr. Houston gives a 

 detailed report of the bacteriological examination of normal 

 human dejecta, and of the intestinal contents of sea-fowl 

 and of fish. All gulls contained typical B. coli in their 

 excrement in enormous numbers, but guillemots did not 

 contain B. coli of any sort. As regards fish, those obtained 

 " from a source seemingly above all suspicion of objection- 

 able contamination, may contain sometimes apparently 

 typical B. coli in their interior ; in the great majority of 



1 "Thirty-third Annual Report of the Local Goverr.ment Board, 1903-4." 

 Supplement containing the Repoi t of the Medical Officer for 1903-4. 



NO. I904, VOL. 73] 



cases the results were either wholly negative or the microbes 

 that were isolated proved to be atypical in character." 



Dr. Alan Green contributes further observations on 

 chloroformed calf vaccine which prove that the quality 

 of the lymph prepared by this method is of a high order. 



The above brief review shows that this report contains 

 matter of the greatest interest and importance which 

 should be studied by all bacteriologists and by those to 

 whom the care of the public health is entrusted. 



R. T. Hewlett. 



INFRA-RED SPECTRA.' 

 'FilE record of an enormous amount of work on the 

 absorption spectra of organic compounds and emission 

 spei tra of various metals and gases in the infra-red region 

 is given in the volume under notice. The investigations 

 were commenced whilst the author was a graduate student 

 at Cornell University, and completed under the auspices 

 of the Carnegie Institution of Washington. 



Even to summarise the mass of valuable information 

 contained would exceed the limits of our present space, but 

 it may be said at once that, to workers along similar and 

 related lines, these results, and the descriptions of the 

 apparatus and methods whereby they were obtained, are 

 indispensable. 



Part i. occupies nearly seven-eighths of the whole volume, 

 and deals with the absorption spectra of 131 organic 

 compounds up to 15 /*. As is pointed out in the very 

 complete historical review, all previous workers in this 

 subject have abandoned the investigation at 7 /4 for the 

 alcohols and 10 /4 for some few other compounds. 



The description of the apparatus and methods is ex- 

 haustive and invaluable. From oSji to 25/4 a quartz 

 prism was employed, beyond that, and up to 15/4, one 

 made of rock-salt. The source of the radiations was a 

 Nernst lamp "heater," which gives a spectrum of which 

 the energy curve is smooth and continuous. A reflecting 

 spectrometer of 35 cm. focal length was employed for the 

 explorations of the spectrum up to 15 41, and a considerable 

 portion of the work up to 7-5/4 was repeated with a spectro- 

 meter of 1 m. focal length. 



The distribution of the energy in each spectrum was 

 determined by means of a radiometer similar to that devised 

 by Nicholls, but with some modifications. 



The principal reasons for this investigation were the 

 determination of the influence of molecular weight upon 

 absorption spectra, and also the effect of molecular struc- 

 ture. The results show that in different compounds each 

 of these causes in turn acts separately, whilst in other com- 

 pounas the absorption is produced by the combined effect. 



In recording the quartz-prism results the author deals 

 separately with each absorption band in the nineteen com- 

 pounds investigated, whilst in the other results the com- 

 pounds are treated separately, notes being made of the 

 chemical structure and properties of each substance where 

 necessary. 



Numerous tables set out the numerical results in various 

 forms, whilst 140 full-page transmission curves show them 

 graphically. In addition to these the author has written 

 seven brief appendices dealing with side-issues in connec- 

 tion with the apparatus and the investigation and its 

 results. 



In part ii. Mr. Coblentz deals with the infra-red emission 

 spectra of various metals, metallic chlorides (alkalies), and 

 gases. The metals were employed as the poles for the arc 

 producing the radiations, whilst the chlorides were vola- 

 tilised on carbon arcs. The apparatus was very similar to 

 that described in part i., except for a few modifications 

 rendered necessary by the greater intensity and unsteadi- 

 ness of the radiations. 



With the metals, a black-body spectrum due to the 

 oxides, and sufficiently strong to obliterate any emission 

 lines which might be present, was found, and in the alkali 

 chloride spectra no lines were discovered beyond 2 41. Of 

 the gases investigated — in vacuum tubes — N was found to 

 be the only one having strong emission lines in its infra- 

 j red spectrum. CO,, CO, and the vapour of C,H 5 HO were 



1 " Investigation* of Infra Red Spectra." By William W. Coblentz. 

 Pp. vi + 331. (Washington, D.C. : The Carnegie Institution, 1905.) 



