GENERAL MONTHLY MEETING, Monday, April 2, 1894. SIR JAMES CRICHTON-BROWNE, M.D. LL.D. F.R.S. Treasurer and Vice-President, in the Chair. Sydney Walter Barnaby, Esq. were elected Members of the Royal Institution. The Special Thanks of the Members were returned to Mrs. Barton for her present of a Portrait of the late Dr. John Peter Gassiot, M.R.I. The Special Thanks of the Members were returned for the following Donations to the Fund for the Promotion of Experimental Research at Low Temperatures: Professor Dewar Hugh Leonard, Esq. £50 £50 The PRESENTS received since the last Meeting were laid on the table, and the thanks of the Members returned for the same, viz.:— FROM British Museum Trustees-Index of Artists, Vol. I. 8vo. 1893. Catalogue of Vases, Vol. II. 8vo. 1893. Catalogue of Hebrew and Samaritan MSS. 8vo. 1893. Catalogue of Fans and Fan Leaves. 8vo. 1893. Catalogue of Spanish MSS. Vol. IV. 8vo. 1893. Catalogue of Romances, Vol. II. 8vo. 1893. Catalogue of Sanskrit and Pali Books. 4to. 1893. Catalogue of English Coins: Anglo-Saxon Series, Vol. II. 8vo. 1893. Catalogue of Cuneiform Tablets, Vol. III. 4to. 1893. Accademia dei Lincei, Reale, Roma-Atti, Serie Quinta: Rendiconti. Classe di Scienze fisiche, matematiche e naturali. 1o Semestre, Vol. III. Fasc. 4, 5. 8vo. 1894. Akerblom, P. Esq. (the Author)-De l'emploi des Photogrammètres pour mesurer la hauteur des nuages. 8vo. 1894. Astronomical Society, Royal-Monthly Notices, Vol. LIV. No. 4. 8vo. 1894. Bankers, Institute of-Journal, Vol. XV. Part 3. 8vo. 1894. Bavarian Academy of Sciences, Royal-Sitzungsberichte, 1893, Heft 3. 8vo. 1894. British Architects, Royal Institute of Proceedings, 1893-4, Nos. 9, 10. 4to. British Astronomical Association—Journal, Vol. IV. No. 4. 8vo. 1894. Cambridge Philosophical Society-Transactions, Vol. XV. Part 4. 4to. 1894. Chemical Industry, Society of-Journal, Vol. XIII. No. 2. 8vo. 1894. Civil Engineers, Institution of-Minutes of Proceedings, Vol. CXV. 8vo. 1894. Corporation of the City of London-Royal Commission, 1893. City of London. Crawford and Balcarres, The Earl of, K.T. F.R.S. M.R.I. 8vo. 1881. Collations and Notes: No. 1, Sanderi Brabantia, 1656-95. 4to. 1893. No. 2, Flower's Mosaic Pavements. 4to. 1883. No. 3, Grands et petits voyages of De Bry. 4to. 1884. Hand list to the early editions of the Greek and Latin writers of ancient and mediæval times. 8vo. 1885. The works of Comte Auguste de Bastard d'Estang. 8vo. 1886. Catalogue of Ballads. 4to. 1890. 1886-93. Early Bindings exhibited by the Earl of Crawford. 8vo. 1886. Analyst for March, 1894. 8vo. Athenæum for March, 1894. 4to. Brewers' Journal for March, 1894. 4to. Chemical News for March, 1894. 4to. Chemist and Druggist for March 1894. 8vo. Electrical Engineer for March, 1894. fol. Electrical Engineering for March, 1894. Electrical Review for March, 1894. Electricity for March, 1894. 8vo. Electric Plant for March, 1894. 8vo. Engineer for March, 1894. fol. Engineering for March, 1894. fol. Horological Journal for March, 1894. 8vo. Industries and Iron for March, 1894. fol. Ironmongery for March, 1894. 4to. Iron and Coal Trades Review for March, 1894. 8vo. Lightning for March, 1894. 8vo. Machinery Market for March, 1894. 8vo. Monist for March, 1894. 8vo. Electrical Engineers, Institution of—Journal, Vol. XXIII. No. 109. 8vo. 1894. Florence, Biblioteca Nazionale Centrale-Bolletino, Nos. 197, 198. 8vo. 1894. Franklin Institute-Journal, No. 819. 8vo. 1894. Geographical Society, Royal-Geographical Journal for Feb. 1894. 8vo. Geological Institute, Imperial, Vienna-Verhandlungen, 1893, Nos. 16-18. 8vo. Institute of Brewing-Transactions, Vol. VII. No. 5. 8vo. 1894. Johns Hopkins University—American Chemical Journal, Vol. XVI. Nos. 2, 3. Linnean Society-Journal, No. 207. 8vo. 1894. Manchester Geological Society-Transactions, Vol. XXII. Part 15. 8vo. 1894. Massachusetts Institute of Technology—Technology Quarterly, Vol. VI. No. 3. 8vo. 1893. Mechanical Engineers, Institution of-Proceedings, 1893, No. 4. 8vo. Norman, C. C. Esq. (the Proprietor)-London County Council Debates, Vol. II. No. 9. 8vo. 1894. North of England Institute of Mining and Mechanical Engineers-Transactions, Vol. XLII. Part 5; Vol. XLIII. Parts 2, 3. 8vo. 1893-4. Odontological Society of Great Britain-Transactions, Vol. XXVI. No. 4. 8vo. 1894. Payne Wm. W. Esq. and Hale, Geo. E. Esq. (the Editors)—Astronomy and AstroPhysics for March, 1894. 8vo. Pharmaceutical Society of Great Britain-Journal for March, 1894. 8vo. Royal Society of London-Proccedings, No. 331. 8vo. 1894. 8vo. Saxon Society of Sciences, Royal-Mathematisch-Physische Classe, Berichte, 1893, Nos. 7-9. 8vo. 1894. Philologisch-Historische Classe, Berichte, 1893, Nos. 2, 3. 8vo. 1894. Selborne Society-Nature Notes for March, 1894. 8vo. Smithsonian Institution-Annual Report to the end of June, 1891. 8vo. 1893. Society of Antiquaries—Proceedings, Second Series, Vol. XIV. No. 4. 8vo. 1893. Archæologia, Vol. LIII. Part 2. 4to. 1893. Tacchini, Professor P. Hon. Mem. R.I. (the Author)-Memorie della Società degli Spettroscopisti Italiani, Vol. XXIII. Disp. 1, 2. 4to. 1894. United Service Institution, Royal-Journal, No. 193. 8vo. 1894. United States Department of Agriculture-Monthly Weather Review for Dec. 1893. 4to. 1894. Upsal Meteorological Observatory-Bulletin Mensuel, Vol. XXV. 4to. 1893-4. Vereins zur Beförderung des Gewerbfleisses in Preussen-Verhandlungen, 1894: Heft 2. 4to. 1894. Wright & Co. Messrs. J. (the Publishers)-The Medical Annual for 1894. 8vo. Yorkshire Archæological Society-The Yorkshire Archæological Journal, Part 49. 8vo. 1894. WEEKLY EVENING MEETING, Friday, April 6, 1894. SIR RICHARD WEBSTER, G.C.M.G. M.P. Q.C. LL.D. Vice-President, in the Chair. PROFESSOR VICTOR HORSLEY, M.B. B.S. F.R.C.S. F.R.S. M.R.I. The Destructive Effects of Projectiles. THE effects of small projectiles when driven at high velocity through the tissues of the brain have always excited the deepest interest, for very obvious reasons. This interest must always be two-sided, namely: (1) Physical; (2) Pathological; and it is upon these two points of view that I propose to speak to you this evening. Conceive a cylindrical bullet with a conical head flying through the air some ten or fifteen times faster than an express train. We have now to study what it is doing in its aerial flight, and what will happen when that terminates by the projectile striking both hard and soft substances. This embodies matter for the purely physical side of the work. But imagine, further, that the hard and soft substances just mentioned are the skull and brain respectively, what will happen then? This is the pathological part of the question, and it is one of the greatest moment; for whereas it is true that a few persons do survive being shot in the head, the large majority die; and it is my object to show you how a combination of physical and pathological experiments has revealed the reason why the majority do die, and revealed it, fortunately, so distinctly as to suggest means for warding off the fatal result. 1. Physical Considerations. First take the case of a bullet flying through the atmosphere. Here in this extremely beautiful photograph, kindly lent me by Professor Boys, you observe that the bullet drives before it a wave of compressed air. Now this compressed air-wave is what is popularly called the wind of the shot, and to it used to be ascribed by military surgeons a certain proportion of deaths. The origin of this theory is difficult to discover, as the only case I am aware of in which the post-mortem examination did not reveal hæmorrhage, fracture, &c., indicating that the shot had actually struck the body (though without injuring the highly elastic skin), is the instance given by the great Russian military surgeon, Pirogoff, in Even this his interesting surgical experiences of the Crimean war. instance finds à priori a more reasonable explanation in syncope, and we shall see directly that the wind of the shot not only cannot under any circumstances kill a man, but also that its energy is far too slight for it to have any destructive effect whatever. It is rather curious to find that but few attempts have been made directly to estimate the wind of the shot, and those by Pelikan and others are only for large shot and by too coarse methods to be applicable in the case of a bullet, as the following experiment shows. An extremely light vane of paper carrying a delicate mirror is suspended to a cocoon fibre, and carefully protected from currents of air in the room. A very gentle puff causes the vane to fly out most vigorously, yet we shall find that the 380 bullet moving 1000 feet a second may pass within 8 inches of it without causing the least deviation of a ray of light reflected from the mirror. It is only when the bullet passes within an inch or two of the edge of the vane that there is some slight rotation. The 303 magazine service rifle, with a velocity of twice that of the larger bullet, produces little more than the same result. It is therefore obvious in this case that the far higher velocity is more than compensated for by the lesser sectional area of the projectile displacing the air. Although there was no proof of much displacement of the air, it was pretty generally held that when the bullet entered any substance the compressed air driven before it exercised an explosive effect. This opinion was more particularly supported by the Belgian physicist Melsens, who actually described it by the term "projectile air." The matter was taken up from the point of view of pure physics, and Magnus demonstrated that if a body like a bullet entered water, e.g. in falling the funnel which the displaced water makes in the axis of the body as soon as that is fully immersed, entangles air, and that it is this air which is carried by the body into the fluid, rather than that any air is forced in in front of the bullet. In answer to Magnus, Laroque invented the following ingenious experiment. He allowed a long body, incapable of wholly sinking, to drop into the water, and then found that there was air driven in in front of it; while, by the nature of the experiment, he had, of course, excluded the possibility of any air following the base of the projectile. I have repeated all these experiments (employing in Laroque's a slender rod of wood) and found that while his contention that air is driven in front of the bullet is completely substantiated, yet Magnus' observation is so far correct that air is also drawn in after it, the fact being that the two conditions are not opposed but simultaneous. Magnus' view was further supported by the adverse criticism of the theory of projectile air of the celebrated French artillerist Morin, which criticism amounted to this, that when a projectile was directed against a solid body it must necessarily follow that so elastic a substance as air should be completely reflected from the surface. I should like to draw your attention to this word solid, because I believe that in that we find the key to the difficulty, and |