250 



NA TURE 



[January 14, 1892 



sixtieth part of a day's destruction in the Formby Channel, it is 

 a wonder that there are any left. 



A point emphasized in the review, but seemingly missed by 

 Mr. Walker, is that the young fish are always promptly returned 

 to the sea by the Solway shrimpers, and the fact that the 

 industry flourishes in spite of the delay so caused shows that the 

 destruction which ensues from the practices described by Mr. 

 Walker is quite unnecessary. Dr. Fulton has experimentally 

 proved that the proportion of young flat-fish of a certain size 

 (say above an inch) that would not survive if returned to the 

 sea is small, so that it is evident that Mr. Ascroft's "axiom 

 that 90 per cent, offish that come on board a boat is destroyed " 

 holds good from no fault of the trawl itself, but simply from a 

 discreditable carelessness on the part of the man. 



Mr. Walker's experiences at the mouth of the Dee show that 

 the shrimps and the young soles (species ?) have different habitats 

 in that river, so that his suggestions as to the limitation of 

 shrimp-trawling seem rather superfluous, since it may be 

 supposed that the trawler would fish where he knew he could 

 get shrimps, and not go out of his way to catch what he did not 

 want. I have noticed myself on the west coast of Ireland 

 that the minute post-larval flat-fish, smaller than those dealt 

 with by Fulton, and which are undoubtedly killed by the 

 meshes of the shrimp-trawl, were never taken on ground 

 frequented by shrimps, where, indeed, as one may judge from 

 the relations of the two forms in captivity, the weaker would 

 have a poor chance of surviving. 



Everyone will agree with Mr. Walker that it is most necessary 

 to ascertain the habitat of the young fish at different times of 

 the year, and to this end the energies of the Marine Biological 

 Association in England, the Fishery Board in Scotland, and 

 the Royal Dublin Society in Ireland, have been for some time 

 directed ; and the assistance that might be rendered by a series 

 of observations by one possessing the experience and oppor- 

 tunities of Mr. Walker would be incalculable. Until, how- 

 ever, our knowledge on the subject is much more complete, I 

 question the advantage of strewing boulders about the bottom 

 of the sea. Even if they remained to accomplish their purpose 

 of interfering with trawling, there is the danger that they would 

 form an attractive shelter, not to the young flat-fish that stand 

 in no need of it, but to some of their natural enemies. 



Dublin, December 27, 1891. Ernest W. L. Holt. 



A New Precessional Globe, 



To facilitate the understanding of the effects of precession, I 

 have made a new arrangement of the celestial globe. A globe 

 mounted in the new way can give a representation of the starry 

 heavens for every place on the earth, and for any date, both past 

 and future. 



The globe is fastened in a ring, so that it can be turned round 

 an axis that goes through the poles of the ecliptic, but can also 

 be fixed in any position by a pair of screws. The amount of 

 turning is to be measured by a divided circle. 



The ring above mentioned — which we will call ring I. — is 

 movable in another ring (ring II.), round an axis, which forms 

 a right angle with the axis formerly mentioned. The inclina- 

 tion between ring I. and ring II. can be measured by an index ; 

 it must equal the obliquity of the ecliptic. 



Ring II. is fastened finally in a third and extreme ring (ring 

 III.), so that it can be turned round an axis which forms an angle 

 of 90° with the axis of ring II. Ring III. is mounted on a stand 

 with a horizon-circle, so that its axis can be inclined at pleasure 

 to the plane of the horizon-circle. The inclination may be read 

 on a scale engraved on ring III. 



To adjust the apparatus to show the firmament at any 

 appointed place and time, one must place ring III. so that its 

 inclination towards the horizon-circle equals the latitude of the 

 place. Then ring II. must be turned so that its plane coincides 

 with the plane of ring III. The angle between I. and II. must 

 be equal to the obliquity of the ecliptic at the appointed time. 

 Finally, the globe must be turned round the axis which goes 

 through the poles of the ecliptic, till the point of the heaven, 

 which is the celestial pole for the time appointed, comes under 

 the ax.s round which ring II. turns in ring III. If the globe is 

 then fastened in ring I., and ring I. in ring II., with screws, by 

 turning the globe in ring III. one can see at a glance which stars 

 are setting and rising, and which are always above the horizon. 



By making Vega, for example, the celestial pole (14,000 A.D.), 



NO. II 59, VOL. 45] 



one can see immediately that for the latitude of London at that 

 remote period, the Cross would be seen at the southern horizon,, 

 and that Sirius then did not rise at all. K. Haas, 



Vienna. 



Simple Proof of Euclid II. 9 and 10. 



In Nature of December 24 (p. 189) a simple proof of 

 Euclid II. 9 and 10 is given, which it is stated is believed to be 

 new. It may therefore be of interest to your readers to know 

 that these proofs are given in an edition of Euclid which we 

 have now in the press. As the author, Mr. Brent, is resident 

 at Dunedin, New Zealand, we are unable to state whether he 

 lays claim or not to any originality in respect to them : in any 

 case, as he has been engaged in mathematical teaching for many 

 years, these and similar proofs of other propositions in Euclid 

 II. have clearly been more widely employed than has been 

 supposed. Percival and Co. 



34 King Street, Covent Garden, London, January 4. 



THE ALLEGED DISCOVERY OF A BACILLUS 

 IN INFLUENZA. 



FROM the behaviour of influenza as an epidemic, it 

 seems not unreasonable to suppose that it may 

 have as its cause a living and multiplying organism ; 

 and when influenza reappeared, after an interval of many 

 years, in the latter part of 1889, and more especially 

 since its communicability from person to person, for- 

 merly disputed, has come to be generally admitted, the 

 public mind, medical and lay, has been in expectation 

 of the announcement that a specific microbe had been 

 discovered as the cause of the disease. 



Even in diseases, however, of which the characters 

 point rriost strongly to a parasitic microbe as their cause, 

 the discovery of such an organism is by no means an 

 easy matter. Thus, no micro-organism has as yet been 

 identified as the cause of small-pox, although this -disease 

 is always more or less with us ; breeds true ; has distinct 

 characters, and a definite localization on the skin ; and 

 propagates by a contagion which retains its activity for 

 very long periods — circumstances which point to a specific 

 organism as its cause, and might be thought to facilitate 

 its discovery. 



From a priori considerations we must suppose the 

 properties of the hypothetical influenza microbe to be 

 as follows. The dififusibility of the poison through the 

 air shows that it must be very minute and readily sus- 

 pended. For the same reason it must belong to the 

 class of aerobic organisms, i e. those for whose existence 

 oxygen is necessary, or at any rate not hurtful. It must 

 multiply with extreme rapidity. It must be capable of 

 multiplying in the bodies, or secretions, of human beings ; 

 and probably also in some medium or media outside the 

 human body— perhaps on damp ground-surfaces, or in 

 confined air laden with dust and organic matter. One 

 can hardly suppose it capable of multiplying in pure air, 

 as it would lack pabulum ; perhaps, as Dr. Symes 

 Thompson suggests, particles of organic dust floating 

 in the air may serve as rafts for it to live on. As, how- 

 ever, influenza prevails under the most opposite conditions 

 of season, climate, and weather, our supposed microbe, if 

 it can live in the air, must be able to flourish under a 

 great range of temperatures and degrees of humidity. I 

 am not aware of any instances of long retention of con- 

 tagion, such as would lead us to postulate the possession 

 by our microbe of resting spores. From these con- 

 siderations we might have expected that it would be more 

 likely to turn out to be a micrococcus than a bacillus. 



From what is known of the pathology of some other 

 diseases of microbic origin, as tetanus and diphtheria, 

 it seems possible that the immediate cause of the 

 symptoms of influenza may be the presence in the blood 

 and tissues, not of the microbe itself, but of the poison 



