6l2 



NA TURE 



[May 13, 1922 



history that are passed in the stomach, muscles, and 

 body-cavity of the mosquito, and of the necessary 

 intermediation of the insect in the spreading of filarial 

 disease among men, were made by a busy medical 

 practitioner, working alone in China, in 1877. They 

 were reported at a meeting of the Linnean Society 

 held in March 1878; they were published in the 

 zoology section of the Society's Journal for 1879; 

 and an amplified account, with a plate of 46 figures 

 representing every stage of the worm's development 

 in the mosquito, from embryo in the stomach to 

 larva in the body-cavity, subsequently appeared in 

 the Transactions of the Society for 1884, at p. 367. 



Not even the loneliest man, of course, works alone ; 

 as Carlyle says, " all past inventive men work with 

 him there/' But in workers there are varieties of 

 aptitude and varieties of circumstance ; and in 

 discoveries there are varieties of worth. The dis- 

 coveries of the highest class are those that enlarge 

 the boundaries of science, that increase understanding, 

 and open out new fields of action. The discoveries, 

 worked out in unpromising circumstances, by that 

 great original genius Patrick Manson, and reported 

 to the Linnean Society in March 1878 and 1884, 

 were of this kind : they estabUshed a great luminous 

 principle of pathogenesis — the principle of the 

 necessary intermediation of the bloodsucking insect : 

 and of every man who applies this principle anew it 

 may be truly said that always in the background 

 Patrick Manson, may peace be with him — acknow- 

 ledged or forgotten—" works with him there." 



A. Alcock. 



Nectar-Sipping Birds. 



The device of Mirafra A ssamica to reach the nectar 

 in the flowers of Castan'ospermum (noted in Nature 

 of April 15, p. 489) has its parallel among British 

 birds. The blooms of several Asiatic species of 

 rhododendron contain much honey, and many of 

 these are defaced at this season by the great tit (Parus 

 major), the blue tit (P. cceruleiis), and probably the 

 coal tit [P. ater) pecking holes in the tube of the 

 corolla and tearing away the upper petals to get at 

 the nectary. In some gardens bumble-bees have 

 learnt to make a similar short cut to the nectary of 

 Salvia patens ; the legitimate entrance, which is 

 furnished with a neat mechanism to ensure cross 

 fertilisation by humming-birds or long-tongued 

 Lepidoptera, being too narrow to permit access for 

 Bombus. Knowledge of the trick, however, is not 

 universal among bumble-bees ; for I have found that 

 in some gardens the blossoms of this Salvia remain 

 intact. . Herbert Maxwell. 



Monreith, Whauphill, Wigtownshire, N.B. 



Aeroplane Crashes : The "Hole in the Air," 

 the " Spin." 



The kind of accident in which Sir Ross Smith and 

 Lieut. John Bennett lost their lives appears to be 

 due to an attempt on the part of the pilot to change 

 the direction in which the aeroplane is moving more 

 abruptly than is consistent with its momentum. 

 Suppose, for example, that the aeroplane could be 

 instantly turned round to face the point from which 

 it had come, its momentum would inevitably cause 

 it to travel an appreciable distance tail first. An 

 approach to this condition constitutes the " hole in 

 the air " of the early airman, and is the harbinger 

 of the " spin " : it is the equivalent of " skidding " 

 in the motor-car and is due to exactty the same 

 cause, namely, momentum run riot. 



As the motion of translation through the air (the 

 one essential condition to the flight of heavier-than- 



NO. 2741, VOL. 109] 



air machines) is being lost the aeroplane begins to 

 fall, and it is difficult to imagine that the pilot can 

 do anything to arrest the fall except perhaps when it 

 accidentally takes the form of a slanting nose-dive. 

 Immunity from this class of accident can only be 

 attained by judicious " banking " on curves of a 

 radius suitable to the aeroplane and its velocity at the 

 moment, and the complete avoidance of quick-turning 

 movements undertaken for any purpose. Is it possible 

 that in some aeroplanes the steering appliance is 

 unnecessarily powerful and apt in that respect to 

 deceive the pilot ? W. Galloway. 



The Athenaeum, April 18. 



Dr. Galloway directs attention to an important 

 aspect of aviation in his reference to a recent accident. 

 The type of failure — a spinning nose-dive — is un- 

 fortunately too common, and on any reasonable 

 statistical basis may be expected to remain so until 

 improved aeroplane design is achieved. Whilst 

 rapid turning facilitates " spinning " the fundamental 

 cause is peculiar to the aeroplane and a property 

 of wing form and arrangement. The support for an 

 aeroplane arises from the aerodynamic characteristics 

 of the wings, and a fundamental change occurs when 

 the angle of attack exceeds some 15 or 20 degrees. 

 Above this critical angle the ordinary motion of an 

 aeroplane is extremely unstable and the natural 

 motion is a spin with the nose well down ; the 

 details of the instability are clear, but the remedy 

 is unknown and only dimly foreseeable. The diffi- 

 culty put before the pilot by the instability is 

 accentuated by simultaneous loss or reversal of 

 control. Scientific research is here required ; it is, 

 indeed, very urgently needed, but the prospects of 

 obtaining the opportunity are far from good. Finan- 

 cial stringency and insufficient sympathy for research 

 by the Air Ministry are the great difficulties, and not 

 lack of scientific ability in the country. It is to be 

 regretted that the loss of famous men is required to 

 give point to a problem of long standing and that 

 the Aeronautical Research Committee has not the 

 necessary authority to carry out work which its 

 reports show that it recognises as very important. 



L. Bairstow, 



The Blood-cells'of the"Oyster. 



The blood-cells (leucocytes) of the oyster have 

 been a subject of great interest ever since Lankester 

 first observed them crawling on the outside of the 

 body parts of the oyster. Recently I have found 

 that these leucocytes will live for 3 or 4 days in sea- 

 water in dishes. If the leucocytes be set free by 

 teasing up the heart of an oyster or by placing pieces 

 of the palps or bases of the gills in sea-water in a 

 petri dish, they are seen at first to be aggregated 

 mainly in masses, but within ten minutes to half-an- 

 hour it will be found that the leucocytes are spread 

 over a large portion of the dish and creeping away 

 from the masses in a flattened amoeboid condition 

 on the bottom of the dish or even on the surface film. 

 At the end of 3 or 4 days the cells round off and die. 

 The length of time they remain alive, however, should 

 make these leucocytes — which are very easily obtain- 

 able — valuable as subjects for physiological investiga- 

 tions, and further, suggests that it might be possible 

 to cultivate them in an appropriate medium under 

 appropriate conditions. 



The mode of propagation of leucocytes in oysters 

 is not known, and certainly no definite organ is 

 known to produce them. A division of a living 

 leucocyte has been observed to the extent that the 

 resulting halves could be seen to be separated only by 

 a relatively very long and very fine connecting thread. 



