428 



NATURE 



[January 26, 191 i 



Gaskell : The action of X-rays on the developing chick. 

 No difference was observed in the action of X-rays upon 

 any one tissue rather than another. The action is con- 

 fined to the lowering of the mitotic activity of the grow- 

 ing tissues. If this diminution is not too great, complete 

 recovery occurs, and the chicks hatch out at the usual 

 time. If the diminution is above a certain degree, re- 

 covery does not take place, and further development is 

 arrested forthwith. The critical dose, which just prevents 

 recovery, varies . with the stage of development of the 

 embryo, decreasing as the mitotic index decreases. The 

 " mitotic index " as defined by Minot represents the 

 number of mitoses per looo cells in the various tissues of 

 embryos of various ages, and he has shown that through- 

 out embryonic life a rapid diminution of mitotic activity 

 is going on. He calls the figures obtained the mitotic 

 index for that particular tissue. — ^Colonel Sir David Bruce 

 and Captains A. E. Hamerton and H. R. Bateman. 

 (Sleeping Sickness Commission of the Royal Society, 

 Uganda, 1908-10.) Experiments to ascertain if antelope 

 may act as a reservoir of the virus of sleeping sickness 

 (Trypanosoma gambiense). It is known that the tsetse- 

 flies (Glossina palpalis) around the northern shores of the 

 Victoria Nyanza still retain their infectivity for sleeping 

 sickness, in spite of the fact that the native population 

 was removed from the lake-shore some three years ago. 

 A series of experiments was, therefore, carried out to 

 ascertain if the antelope, which are fairly common along 

 the uninhabited shores of the lake, were capable of acting 

 as hosts of the parasite of sleeping sickness. Eleven 

 antelope of the waterbuck, bushbuck, and reedbuck species 

 were obtained from a district where tsetse-flies and sleep- 

 ing sickness did not exist. Blood from these animals was 

 first inoculated into monkeys to ascertain if they were 

 already naturally infected with trypanosome disease. 

 They proved to be healthy in this respect. Tsetse-flies 

 (Glossina palpalis) that were known to be infected with 

 the virus of sleeping sickness were then fed upon each of 

 the eleven antelope. After about eight days the blood of 

 these animals was again inoculated into susceptible 

 animals, with the result that the latter became infected 

 with Trypanosoma gambiense in every case. In eight 

 out of the eleven buck under experiment Trypanosoma 

 gambiense appeared in their blood for a few days only 

 (some seven to twelve days) after they had been bftten by 

 infected flies. Flies that were hatched out in the labora- 

 tory, and had never fed before, were now fed upon the 

 infected antelope, and subsequently upon monkeys. After 

 an interval of about thirty days, required for the develop- 

 ment of trypanosomes within the fly, monkeys were in- 

 fected with sleeping sickness from the antelope by the 

 agency of Glossina palpalis in sixteen out of twenty-four 

 experiments. On dissecting the flies which had been fed 

 upon the infected antelope, it was found that io-8 per cent. 

 of them were infected with Trypanosoma gambiense. The 

 highest percentage of infected flies in any one of the 

 positive experiments was 2 1 per cent. ; the lowest was 

 1-3 per cent. Nine of these antelope infected with 

 Trypanosoma gambiense were under daily observation for 

 more than four months. They remained in perfect health. 

 Two of them (a waterbuck and a bushbuck) never showed 

 trypanosomes in their blood, although examined every day. 

 Both these antelope-infected flies fed upon them, one of 

 them as long as fifty-five days after its infection. No wild 

 antelope inhabiting the lake-shore has yet been found to 

 be naturally infected with Trypanosoma gambiense. — 

 Colonel Sir David Bruce and Captains A. E. Hamerton 

 and H. R. Bateman. (Sleeping Sickness Commission of 

 the Royal Society, Uganda, 1908-10.) Experiments to 

 ascertain if the domestic fowl of Uganda may act as a 

 reservoir of the virus of sleeping sickness (Trypanosoma 

 gambiense). There is evidence that tsetse-flies (Glossina 

 palpalis) feed on the blood of birds as well as that of 

 mammals inhabiting the shores of Victoria Nyanza. 

 Domestic fowls, as representing birds, were experimented 

 with in the search for possible hosts or reservoirs of the 

 virus of sleeping sickness. A series of twenty-one experi- 

 ments was carried out to ascertain: — (i) if these birds 

 can, like antelope, be infected with Trypanosoma 

 gambiense by the bites of known infected flies ; (2) if 

 birds so infected can transmit the parasite to newlv hatched 

 Glossina palpalis which had not fed before thev were 

 NO. 2152, VOL. 85] 



allowed to bite the fowls ; (3) if these flies can convey 

 sleepmg sickness to normal monkeys. About 2000 flies 

 many of which had been proved to be infected with viru- 

 lent Trypanosoma gambiense, were fed upon twenty-one 

 domestic fowls. The results were negative in every case, 

 as ascertained by frequent microscopical examination of 

 peripheral and centrifuged heart's blood, and inoculations 

 of the fowls' blood into susceptible animals. Four hundred 

 newly hatched flies were fed upon three of the fowls which 

 had been bitten by infected flies. The former were sub- 

 sequently fed upon monkeys, with the result that they 

 failed to convey sleeping sickness from fowls to monkeys. 

 Two hundred and eighty-three of these flies were dis- 

 sected, and no flagellates could be found in them. Con- 

 clusion. — The Uganda fowl cannot act as a reservoir of 

 the virus of sleeping sickness. 



Institute of Metals, January 18.— G D. BengouKh : 

 Report to the corrosion committee on the present state 

 of our knowledge of the corrosion of non-ferrous metaJs 

 and alloys, with suggestions for a research into the causes 

 of the corrosion of brass condenser tubes by sea water. 

 The report is intended to be a general review of present 

 knowledge of the subject of the corrosion of non-ferrous 

 metals, both in its practical and scientific aspects. The 

 theory of corrosion is considered in some detail, and an 

 attempt is made to lay a broader scientific foundation for 

 the whole subject. Two series of experiments are pro- 

 posed, which, in the author's opinion, should be taken in 

 hand at once. One series is of an empirical nature, and 

 is intended to test the validity of certain opinions held 

 on the subject by practical men, and especially swh 

 opinions as are in dispute between different authoriti 

 The other series, of experiments is of a purely scientii 

 nature, and is regarded as a means of elucidating certain 

 causes of corrosion that have hitherto been obscure. 

 —Engineer Rear-Admiral J. T. Corner : Some prac- 

 tical experience with corrosion of metals. Some of the 

 causes of corrosion of metals on shipboard are so 

 obscure, and the origin so difficult to trace, that a satis- 

 factory explanation is seldom forthcoming. Corrosion of 

 a minor character existed in the old wooden warships, but 

 when iron was used for shipbuilding the conditions were 

 different, and it was soon found that the ships' plates and 

 angles suffered from contact with the copper pipes and 

 bilge water, the Megaera being a case in point, where the 

 copper so affected the ship as to necessitate beaching her j 

 to prevent her sinking. Trouble from corrosion largely 

 increased about the time of the introduction of the electric 

 light afloat. Suggested causes of corrosion were con- | 

 sidered.— Prof. H. C. H. Carpenter and C. A. ! 

 Edwards : A new critical point in copper-zinc alloys : its i 

 interpretation and influence on their properties, with an i 

 appendix, by C. A. Edwards, on the nature of solid I 

 solutions. A new critical point has been found in those i 

 alloys of copper-zinc which contain the )3 constituent. 

 The temperature of this point is 470° C. The physical I 

 meaning of this change is that the ;8 constituent decom- ' 

 poses at 470° C. into the a and y constituents. In the ■ 

 appendix to the paper, Mr. C. A. Edwards concludes that ! 

 a metallic crystalline mass, often described as a solid solu- } 

 tion, is an intimate crystalline mixture, and whilst the I 

 primary crystals are so small that the mass appears quite j 

 homogeneous when viewed under the microscope, they , 

 are sufficiently large to retain their identity.— Prof. A. j 

 McWilliam and W. R. Barclay : The adhesion of | 

 electro-deposited silver in relation to the nature of the | 

 German silver basis metal. This paper gives details of j 

 researches undertaken with the view of determining the i 

 nature of the adhesion of electro-deposited silver to the 1 

 German silver alloys generally used as a basis metal, and ' 

 whether any differences exist between various grades of 

 alloys as to their suitability for use in the manufacture ^ 

 of electro-plate which may be called upon to withstand ! 

 rough usage. The authors find that under the severest 

 conditions of wear there is a great tendency for 

 thick electro-deposited silver coatings to strip from the j 

 alloys of high nickel contents known as firsts, that the ! 

 plating adheres most firmly to the lowest grades known : 

 as fifths, but as these are generally too soft or too weak' 

 for the special purpose, the best medium is found some-i 

 where in the region of the alloys known as thirds. — H. J. 



