636 



NA TURE 



[October 25, 1906 



" Abstracts from tlip Meteorological Observations taken 

 at the Stations of the Royal Engineers (including 15 

 Colonial Stations) in the Year 1,853-4, with Notes on 

 ^leteorological Subjects." 



" Abstracts from the .Meteorological Observations taken 

 at the Stations of the Royal Engineers (comprising 13 

 British and 18 Colonial Stations) in the Years 1853-4, 

 1S54-5, 1855-6, 1856-7, 1857-S, and 1858-9." 



" Abstracts from the Meteorological Observations taken 

 in the Years 1860-61, at the Royal Engineer Office, New 

 Westminster, British Columbia." 



These volumes will be issued without payment. 



I may also mention at the same time that the Meteor- 

 ■ological Committee, acting in accordance with the recom- 

 mendation of the fourth International Conference on 

 Scientific Aeronautics, has undertaken to subscribe for 

 a number of copies of the international publication of the 

 observations of the upper air on the " international days," 

 "which will be issued by Prof. Hergesoll, the president of 

 the commission. I shall be glad to know whether anv 

 scientific institution or library wishes to subscribe for a 

 copy of this publication. The amount of the subscription 

 is U. per annum. \\'. N. Sfiaw. 



The Breeding Habits of the Tsetse-ffy. 



T SHOULD be greatly obliged if you could find space in 

 your columns for the following e.xtracts from a letter which 

 I have received from my friend Dr. .\. G. Bag.shawe 

 announcing the discovery, I believe for the first time, of 

 the pupae of the tsetse-fly (Glossina palpalis) in nature. As 

 this species of fly is now known to be the agent which 

 disseminates the infection of sleeping sickness, any dis- 

 coveries relating to its breeding habits are of the utmost 

 importance from the point of view of devising measures 

 for extirpating the fly or checking its increase. Together 

 with my colleagues Lieuts. Gray and Tulloch, I spent a 

 great deal of time, when I was in Entebbe, in searching 

 for the pupa; of the fly, and we offered the native bovs a 

 rupee each for them, but all our efforts to find therii in 

 nature were unsuccessful, although captive flies deposited 

 great numbers of pupae in our cages. I ought, perhaps, to 

 explain at this point that the tsetse-fly is viviparous, and 

 produces a full-grown larva, one at a time ; the larva is 

 of a light yellowish tint when born, and wriggles about 

 actively for an hour or so, and then turns in a short time 

 to a dark brow'n pupa, about the size of a grain of wheat. 



Dr. Bagshawe, who is already well known for the 

 botanical collections he has sent home, has succeeded where 

 we failed, and as I do not know what steps he has taken 

 to secure the priority for this most important discoverv, I 

 hasten to make it public on his behalf. It will be seen 

 that the pupa; have been found in the banana plantations. 

 Since bananas are the staple food of the Baganda. it would 

 be impossible to destroy the plantations without creating 

 a famine. I may mention, however, that we found the 

 tsetse-fly swarming on the deserted island of Kimmi, on 

 the Victoria Nyanza, where there were no plantations, so 

 that this is perhaps not its onlv breeding place. 



E. A. MiNciiix. 



Lister Institute of Preventive Medicine, October 17. 



(Extract from Dr. Bagshawe's Letter.) 

 " On .August 29 I got them [the pupa'] at last. I had 

 marked down a particular spot as lilvely, and had pitched 

 my camp near by to search, .\long the lake shore for 

 about 100 yards was a belt of bananas 10-20 (40?) vards 

 in width, and behind that undergrowth, going back 100 

 yards or more. Fly were thick and bothered one up to 

 sunset. 



" On the second day one of the porters I had coached 

 brought me a pupa while I w-as searching a hole in a tree. 

 He had found it among the banana rootlets. I searched 

 there at once, and soon found some emptv pupa cases. 

 The next day I had a lot of my people at w-ork and 53 

 pupae were found, all in the loose crumbling soil round 

 the bananas. In the scrub behind there are none to be 

 got. . . . 



"1 made a series of experiments latr'lv to find out how 

 long a stretch of river the individual fly haunts. I started 



NO. TO3O, VOT . 74] 



on the assumption that a fly with five legs is as good as 

 one with six, and if one snipped off a piece of a known leg 

 that fly could be identified when caught again. Six series 

 of experiments could be made. It worked admirably. The 

 experiments want repeating on a larger scale (I hope to 

 do it on the Semliki), but I have shown clearly that the 

 range is nt least a mile. This is the reason why the 

 breeding places have eluded search so long. 



" (Signed) Arthur G. B.\osmawk. 

 " .Albert Edward Lake, September i, 1906." 



Suspended Germination of Seeds. 



I.N Mr. Claridge Druce's letter in Nature of October 11 

 he rightly remarks that in order to prove the suspended 

 germination of seeds over long periods, instances are re- 

 quired in which the factors of wind-carried seedy, &c., can 

 be v/ith some certainty eliminated. The following case, 

 though not absolutely conclusive, may still be of interest. 



Personally I am of opinion that the seed of Digitalis 

 docs preserve its germinating power for a considerable time. 

 .\ few years ago I cleared a space, speaking from memory, 

 of say forty yards by thirty yards, occupied by old Portugal 

 laurels 25 feet to 30 feet high, planted fully sixty years 

 ago, with Rliod. ponticum lining the path in front ; the 

 space, except on the path side, is surrounded by thick 

 coverts. The nearest growing fo.xgloves were to the west 

 along a 6-feet path running parallel with the long side of 

 the cleared area, and distant, say, ten yards ; both sides 

 of this intervening space are lined by old rhododendrons ; 

 seed blown along w^ould fall on the path or the edge of 

 the clearing. The laurels were removed in January and 

 Februarv, when all, or nearly all, the seed would have 

 been shed. Notwithstanding this, the next spring the whole 

 of ihe cleared ground was covered with a uniform carpet 

 of seedlings, practically hiding the bare ground. It seems 

 to nic that, even if some wind-blown seed penetrated the 

 evergreen barrier, the seedlings would have appeared in 

 patches. 



I have known many other somewhat similar instances, 

 but none quite so specialised as the above. 1 may add that 

 the spot is exceptionally protected from wind, having tall 

 forest trees on all sides. 



.ArCIIIEALD BuCllAN-HKI'lirRN. 



Smeaton-Ih pburn, I'restonkirk. 



Biometry and Biology. 



Owing to the proof of my letter in last week's Nature 

 reaching me too late for careful revision, one or two slips 

 escaped notice. Of these, I would wish to direct attention 

 to the interchange of the words intra-racial and inter-racial 

 in the second paragraph on p. 6oq (column i, line 14). 



Karl Pearson. 

 Biometric Laboratory, University College, London, 

 October if). 



.SPEED AND STABILITY IN RAILWAY 

 TRA YELLING. 



THK Salisbury railw.tv accident, being: followed 

 after no very long period by the somewhat 

 similai- disaster at Grantham, undoubtedly raised a 

 feelinj;- of considerable uneasiness in the public mind. 

 The recent publication by the Board of Trade of 

 Major Prinijle's report on the former calamity should 

 do something- to allay this apprehension, if only be- 

 cause it shows that the cause of the derailment of 

 the train was not " mysterious," but is fully to be 

 explained. That the evil we know is less aiarming 

 than one which vaguely threatens is a fact for which 

 we have classic authority. 



The accident occurred on July i at the .Salisbury 

 -Station of the London and .South-\\'estern Railway, 

 the train being the special boat express from Plymouth 

 to London, carrying passengers who had arrived by 

 the .'Xmerican liner New York. The train consisted 

 of four eight-wheeled vehicles hauled by a four- 



