February 28, 1895] 



NATURE 



425 



OUR ASTRONOMICAL COLUMN. 



Origin of the I,unar Formations. — The experiments by 

 which Scrope altempted to reproduce the characteristic features 

 of the moon's surface have been repeated with slight modifica- 

 tions by M. .Stani>las Meunier, and the results which he has 

 obtained are certainly very suggestive, if, indeed, they do not 

 furnish the l<ey to the origin of the various formations which 

 the moon presents tD us. (C(?OT//^y ^-j^wi/r/.?, January 2S.) Plaster 

 is mixed with water in which a little glue has Deen dissolved to 

 prevent too rapid setting, and the mixture is heated in a frying- 

 pan over a gas-burner until ebullition commences ; the gas is 

 suddenly turned off at an opportune moment, and the mass is 

 left to cool undisturbed. Experimenting in this way, and by 

 varying the consistency of the paste, M. Meunier has obtained 

 many features besides the intermingling circular cavities pro- 

 duced by Scrope. The central peaks which are so frequently 

 noticed in lunar craters are reproduced perfectly, being formed 

 at exactly the same time as the circular borders, and even 

 resembling their lunar prototypes iu being generally somewhat 

 lower than the edges of the craters. Further, the artificial 

 craters tend to form in groups of two or three, or even more, 

 and sometimes one ring will envelope several ; some parts may 

 be covered with cavities, with or without central peaks, and 

 relatively large smooth areas at once recall the lunar "seas." 

 If the experiment be carried on until nearly the whole of the 

 water is evaporated, fissure^ also make their appearance. 



13y covering the paste with fine grey sand at the moment it 

 begins to boil, the results are said to be still more striking, and 

 better adapted for photography. 



M. Meunier expresses the opinion that the moon has failed 

 to pass through all the planetary stages, in consequence of the 

 original relative scarcity of fluids, and he believes this concep- 

 tion to be confirmed to some extent by another modification of 

 the experiment, in which the paste is covered with a rather 

 thick layer ol sanii, representing the rocks forming the 

 earth's epidermis ; the "volcanic" manifestations then change 

 character, and more nearly approach terrestrial types. 



7 Cassiopei.f.. — This star has always possessed a special 

 interest to spectroscopic observers since the discovery of bright 

 lines in itsspeclrum by Secchi. Continued observations seemed 

 to suggest a periodicity in the visibility of the bright lines, but 

 this question can now be attacked more completely by the 

 photographic method. Fifty-three photographs, extending 

 over a peiiod ol six years, have been taken at South Kensing- 

 ton, and a first examination of the negatives has led 

 to several important conclusions {Roy. Soc. Proc. vol. Ivii. 

 p. 173). The lines of hydrogen were constantly bright in 

 the period covered by the ph(.tographs, and other bright lines 

 were also seen in all good photographs. Further, the lines of 

 hydrogen are double in all the photographs taken with su.licient 

 dispersion, and the distance between the components is constant 

 within the limits of error in measurement. Other conclusions 

 are that the bright lines of hydrogtn are superposed on broad 

 dark bands, and that there are also other ill-defined dark lines 

 in various parts of the spectrum ; these dark lines correspond 

 very closely with the lines seen in the spectra of (,'Orionis and 

 Itellatrix. *' This at once contradicts Prof. -Scheiner's recent 

 statement that he does not believe it possible that dark lines can 

 exist in the s[)ectrum." Dark lines have also been observed 

 and photogra[)hed by Keeler. 



It will be seen that the spectrum presents numerous peculiari- 

 ties, and an explanation of the physical condition of the star or 

 stars winch produce the different appearances is by no means 

 simple. 



The Identity ok Denninc's and Brorsen's Comets. — 

 It was pointed out in the Ailronomisthe NaehrichUn, No. 3271, 

 that the orbits of the comet 1894 I (Denning), and Brorsen's 

 comet, intersect in heliocentric longitude 285°, and that eaily 

 in l88l the two objects must have been close to one another 

 near the point of intersection (see Nature, January 24, 

 p. y>2). The elements used for the cgmparison were, in 

 the case of Denning's comet, due to M. Schulhof. 

 This computor gives new elements for the comet, in 

 Aslr. Nachr. No. 3276, and expresses an opinion 

 upon the suggested connection. He thinks that the 

 elements compaied, with the exception of inclination, certainly 

 present some points of resemblance. More important, per- 

 haps, is the fact that the point of intersection of the two orbits 

 is nearly their point of nearest apjiroach to the orbit of Jupiter. 



NO. 1322, VOL. 51] 



A' 



Applying M. Tisserand's criterion for the connection between 

 two orbits, the value 0'47 was found for Brorsen's comet, and 

 ©•50 for Denning's. It is therefore concluded that the 

 two comets formed at one time a single body, and that after 

 their separation their orbits were more and more modified by 

 Jupiter. 



THE ANTITOXIC SERUM TREATMENT OF 

 DIPHTHERIA} 



If. 



The Treatment. 



SSUMINGnow that the antitoxic serum is available, how is 

 it to be used? It has been strongly recommended that it 

 should be used not only as a curative or direct therapeutic agent, 

 but that it should also be used as a prophylactic — that is, as a 

 protective agent against possible infection, especially during 

 those periods when diphtheria is rife. It is almost too soon to 

 consider this prophylactic property of antitoxic serum, as for 

 some time to come the energy of those engaged in the prepara- 

 tion and use of this serum must be directed towards obtaining 

 a sufficient supply for the treatment of cases of developed 

 diphtheria. 



Results of this Method of Treatment. 



It may be well to consider what have been the results obtained 

 up to the present, and for this purpose the statistical method 

 will probably carry most conviction, especially if it is possible 

 to give full and accurate detail ; and now that these statistics 

 have been criticised not only by those who have used this treat- 

 ment, but also by those who oppose it because it runs counter 

 to their feelings and ideas, they are every day more and more 

 trustworthy, much fuller, and more valuable. 



It is first necessary to determine the average case mortality 

 in diphtheria for some considerable period before the antitoxic 

 treatment was introduced ; then to see what has been the lowest 

 case mortality during an ecjual and similar period for which we 

 have any statistics ; and lastly, to compare these with the case 

 mortality of the period during which the antitoxic serum has 

 been used. 



In Table I. are given the mean annual death rates from 

 diphtheria per million living in England and Wales and in 

 London, in four periods of three years each. 



Table I. 



i83i-3 1884-6 1887-9 1891H 



England and Wales ... 144 ... l66 ... 173 ... 192 

 London 21.^ ... 227 ... 315 ... 377 



Dr. Sykes gives the following statistics t^ — During the year 

 1892 there were 1962 deaths from diphtheria in London, whilst 

 in 1S93 there were 3265, or neatly twice as many deaths. 



Now let us see what has lieen the case mortality. Statistics 

 after correction give the following results. During 1893 there 

 were 13,694 cases of diphtheria notified in London. The 

 mortality amongst these cases was 3195 (Lancet statistics 

 correcied), or 233 per cent. 



Table II. gives further information, and enables us to see what 

 is the diphtheria case mortality in large well-found hospitals. 



TAni.ElI. — Metropolitan Asylums Hoard : Admissions and Case 

 Mortaliiy, Diphtheria, 1888-93. 



1888 ... . 



1889 ... 



1890 



1891 



1892 



1893 



Note. — Diphtheria cases have only been admitted into the 

 Hospitals since October 23, 188S. 



In Table III. are given statistics dealing with the diphtheria 

 case mortality where the serum treatment has been used. 

 Wherever possible, the case mortality over a considerable 

 period is given in the last column of the table, for purposes of 

 comparison. 



' A lecture delivered at the Royal Institution, on Friday, February 8 

 by Dr. G. Sims Woodhcad. (Coniinued from page 406.) 



