July 7, 1923] 



NATURE 



by continued service. But this personal sacrifice 

 (added to the considerable private expenditure during 

 his investigation) enabled him to complete his work, 

 by demonstrating the applicabihty of its benefits in 

 West Africa and Ismalia. The King-Emperor has 

 conferred honours (not, however, upon the recommenda- 

 tion of the Government of India) upon the man who 

 had made, as Manson said, the discovery of the century 



(p-317)- 



Following the adoption of anti-malaria methods 

 based on knowledge gained by Ross, invaliding and 

 sickness in the British garrisons in the tropics have 

 been reduced to an extent which must represent many 

 thousand pounds— irrespective of human suffering — 

 saved ; great mercantile firms have extended trade 

 to areas they formerly shunned from dread of the 

 malaria fiend, and these share the benefits of commerce 

 consequent upon the opening of the Panama Canal, 

 the construction of which had proved impossible in the 

 hands of the French — owing to the ghastly mortality 

 of employees — in the absence of Ross's methods ; 

 during the great War, according to the Official History 

 (vol. 2, p. 238), " the loss of the strength to the 

 armies from the effects of malaria was great, and 

 hut for the preventive methods adopted it might have 

 been incalculably greater " (italics not in the original). 

 What has the nation, the Parliament of which voted 

 30,000/. to Jenner in token of gratitude, done for this 

 practical philanthropist ? 



In " Memoirs " covering many years and many 

 locahties, the author has left little room for criticism 

 as to accuracy. At p. 223, the date of his first gleam 

 of success is erroneously stated in the text ; fortunately, 

 the next page is faced by a facsimile which correctly 

 shows the date to have been August 20, 1897 ; at 

 p. 327, in referring to Haffkine's good work, it is 

 evident the date 1916 should read 1896 ; at p. 198, 

 in reference to the use of " bird's malaria," the context 

 would show that the intention is to refer to 1896 

 and not 1906. The Madras Presidency can claim 

 freedom from the conception that (p. 200) " though 

 plague had broken out for some years in China, almost 

 no precautions had been taken to exclude it from 

 India." It is inaccurate to describe Mr. E. H. Hankin, 

 the able bacteriologist, as " the discoverer of the mode 

 of purifying wells by permanganate of potassium." 

 He did not initiate the method ; to him is the credit 

 of showing that the cholera vibrio is killed by the 

 chemical, and is not starved out of existence by its 

 action on organic matter. The Hindu title of 

 " Maharaja " used in connexion with the independent 

 potentate mentioned at p. loi will doubtless be 

 <:orrected in future editions of the work. 



W. G. King. 

 NO. 2801, VOL. I 12] 



Variable Stars. 



Specola Astronomica Vaticana V. Herausgegeben von 

 Johann Georg Hagen, S.J., und Johann Stein, S.J. 

 Die Veranderlichen Sterne. Erster Band : Ge- 

 schichtlich-Technischer Teil. Von Johann Georg 

 Hagen, S.J. Pp. xx + 8ii. (Freiburg im Breisgau 

 and London : Herder und Co. G.m.b.H., 1921.) 

 42s. 



THOUGH the subject of variable stars, apart from 

 still earlier beginnings, has been actively studied 

 'for a century, and the realisation of its importance has 

 been reflected in a growing volume of technical litera- 

 ture, it has not hitherto received extended discussion 

 on historical lines in a work exclusively devoted to 

 this branch of astronomy. The first volume of such a 

 work, for which Father Hagen assumed responsibility, 

 has now been completed by the inclusion of a fourth 

 and last part, on the elements of the light-change, the 

 three earlier parts having been issued separately from 

 the year 1913 onwards. The remaining second volume, 

 which will deal with the physical explanations of the 

 phenomena of variable stars, is in the hands of Father 

 Stein, and its appearance will be anticipated with 

 interest. 



In these days, when the insistent demand for sum- 

 maries even to the most condensed papers betrays the 

 fact that honest reading is out of fashion, there is some- 

 thing impressive in an ample and scholarly work like 

 this, with its more than 800 quarto pages. The three 

 earlier parts dealt with the equipment of the observer, 

 the actual observation of variable stars, and the reduc- 

 tion of the observations. References to other methods 

 will be met with incidentally, but it is to the visual 

 method in its historical development that the work is 

 almost exclusively devoted. Naturally there are parts 

 of the subject which are largely independent of the 

 particular method of observation, and the discussion 

 of them will serve a more general application. 



To avoid misconception as to the nature of the work 

 and its limitations, it will be well to refer to an explana- 

 tion given at the outset in the preface. There it is 

 stated clearly that for the principles of photometry, 

 the practical details of astronomical photography, the 

 description of all the various forms of apparatus and 

 those parts of mathematical theory which are involved 

 in the discussion of the observations, the reader must 

 consult in each case the appropriate text-book or even 

 an encyclopaedia. To this it should be added that 

 the book contains no figures or illustrations, and that 

 very little space is occupied by tabular matter. Thus 

 it is in no sense a text-book suitable for the needs of the 

 ordinary observer, but an historical work from which 

 the lessons of past experience can be derived from 



A I 



