June 25, 1903] 



NATURE 



171 



problem which awaits the Admiralty in the future, arid 

 which, if faced along the whole line, at the same time, 

 may prove of Herculean proportions and be fraught 

 with dangers of breakdowns, must commend itself 

 as a scientific method. Our view of the wisdom 

 of such an interchangeability among the present officers 

 is strengthened by information which has been fur- 

 nished us as to the procedure in the German Navy, 

 \\ hich enables us to compare the two systems, and in 

 our opinion fully justifies the policy of the new cir- 

 cular. 



The distribution of duties amongst executive officers 

 of the German Navy is as follows. As in the British 

 Service every officer is educated in seamanship, 

 navigation, gunnery and torpedo service. In the 

 course of their service the various qualifications of 

 the officers are carefully noted, and especially if 

 they show superiority in any one of the above-men- 

 tioned branches. Ships in the German Navy are com- 

 missioned for two years. The list of officers for any 

 given ship is made out by the Admiralty at Berlin. 

 The next senior officer after the captain becomes the 

 executive officer. After him the officer who is most 

 proficient (according to the returns) in navigation and 

 pilotage is appointed as navigating officer, without re- 

 gard to seniority as lieutenant. He who is most 

 proficient in gunnery is appointed " artillery officer," 

 and so with the torpedo officer. Qualification regulates 

 the selection of each officer for special duties, not his 

 seniority as lieutenant. The specialisation of an officer 

 for any particular duty only lasts for the two years' 

 commission. In the next commission the navigating 

 officer may be artillery or torpedo officer, or an ordinary 

 watch keeper without special duty. It is exceedingly 

 rare for an officer to be appointed for navigating duties 

 for more than two years, as the Admiralty require 

 every officer to go through a probation as navigator in 

 order to ensure that captains who are responsible for 

 the navigation of the ship shall know their work in 

 that respect. An apparently weak point in this system 

 is that for a time after the appointment of an officer 

 to navigating duties ships are not so well navigated 

 as they might be, since for the first few months of his 

 time the navigator is really learning his work. 

 Gunnery and torpedo work may be learnt in harbour, 

 but navigating can only be learnt by actual practice 

 and experience at sea. But, on the other hand, the 

 strength of this system is that all officers have practical 

 training at sea as navigators with a captain who has 

 gone completely through the navigating mill, and 

 knows how to detect any failure in the navigator which 

 might endanger the ship. For squadrons an officer 

 who has shown good ability as navigator in a single 

 ship is selected as navigator. 



On this system, whilst ability in any branch (N., G. 

 or T.) is recognised, an officer is not unduly specialised 

 to the detriment of his knowledge in other branches 

 of his profession. In the British Navy the gunnery 

 and torpedo officers are occupied with their special 

 duties nearly the whole of their time as lieutenant, but 

 they go to deck duties when promoted commander, 

 although their knowledge of navigation and the hand- 

 ling of the larger ships is practically nil. But the 

 NO. 1756, VOL. 68J 



navigator is occupied in special duties when promoted 

 commander as well as during his service as lieutenant, 

 some fifteen years in all at least, and is allowed no 

 practice in other branches of a naval officer's pro- 

 fession, and because he has not been allowed to have 

 any such practice, he is discharged to the coast guard, 

 his naval career is broken, and the Service loses a man 

 who has had the best possible training for leading 

 ships into action. 



Surely this comparison shows that the question ot 

 interchangeability has already been considered in the 

 German Navy on the lines which we indicated as bene- 

 ficial for our own ; and in this we see an additional 

 argument why the preliminary trial which we sug- 

 gested on scientific grounds in our own Navy, and to 

 which the Admiralty now stands committed, should 

 at all events be welcomed as a first step to the wider 

 interchangeability to which the Admiralty is certain to 

 be forced in the future, for of the progress and need 

 of science in the armed service of a nation there will 

 be no end. 



THE DISTRIBUTION OF DISEASES. 

 The Geography of Disease. (Cambridge Geographical 

 Series.) By Frank G. Clemow, M.D. Edin., 

 D.P.H. Camb. Pp. xiv + 624. (Cambridge : 

 University Press, 1903.) Price 155. 6d. 



THE present writer had occasion recently to en- 

 deavour to ascertain, from the literature avail- 

 able in London, the distribution of a particular tropical 

 disease. After spending several months on the work, 

 the conclusion left on his mind was that the task was 

 impossible in London alone, and that similar work in 

 continental libraries would have to be undertaken 

 before an accurate idea could be obtained. There is 

 another method possible in the study of distribution, 

 viz. personal investigation in various countries into the 

 occurrence of a particular disease. The difficulties in 

 the way of this method are perhaps not so great as one 

 would think. 



A notable instance of what we mean has lately been 

 afforded by Hutchinson in his study of the " fish "" 

 setiology of leprosy. Not content with accepting all 

 evidence second-hand, he proceeded to South Africa and 

 India and inquired critically into the statements which 

 had been made against his view, with the result that 

 many if not all of the " facts " (such as p. 229, " leprosy 

 is found to be common in people whose religion and 

 customs forbid them to touch fish ") quoted as opposed 

 to his views he was easily able to show were not facts 

 al all, but mere hearsay evidence, which by constant 

 repetition is at last generally believed. Many instances 

 of this kind have come within the writer's own ex- 

 perience. Thus when first the mosquito malaria theory 

 was definitely established on a basis of fact, it was 

 asserted in print over and over again that no mosquitoes 

 existed in such a place, but that malaria was rife there. 

 As it was important to examine into these statements, 

 the circumstances were carefully investigated in each 

 particular instance, with the result that the " facts '* 

 vanished into thin air. 



Another striking example is Manson's theory of 



