NA TURE 



[Dec. 23, 1886 



savage marauders and pirates, the South Illyrians, four centuries 

 B.C., had been thoroughly amalgamated with the Macedonian 

 and Epirote nations, adopting tlie pre- Hellenic form of speech 

 of those peoples, which still lingers in the spoken tongue of the 

 modern Albanians. After the incursions of Finns and Slavs 

 into the Balkan and Danube territories, in the sixth and seventh 

 centuries, the remnant of Illyrian and other primitive races that 

 escaped extermination were comprised under the general name 

 of Albanians ; and Dr. Zampa believes that in the mountainous 

 districts of Scutari we find the purest representatives of the 

 ancient Albanian race. In this region, therefore, he has 

 sought the data necessary for the elaboration of the compara- 

 tive anthropological researches of the ethnic relations and 

 differences existing between the Italian and other branches of 

 the Albanian peoples. The author gives at length the results of 

 his measurements of several series of crania obtained in Dal- 

 matia, comparing them with those taken from living subjects ; 

 and although it cannot be said that his researches decide the 

 question whence the .Albanian Italians derive their origin, they 

 throw important light on the early history of the primitive races 

 of the Balkan Peninsula, and on their gradual amalgamation with 

 the numerous invaders and alien settlers who, in the course 

 of ages, have occupied the lands of the ancient Illyrians. — 

 On trephining, as practised in jMontenegro, by M. Vedrenes. 

 The question of prehistoric trepanning, which first excited atten- 

 tion about ten years ago, has led to the consideration of the 

 hitherto almost unnoticed fact that cranial trephining has been 

 practised in Europe from the most remote ages to the present 

 day. Indeed, according to M. Vedrenes, the operation is also 

 of frequent occurrence among the natives of .^ures, in Algiers, 

 where it is held in high esteem as being both safe and bene- 

 ficial. Here it is generally used to arrest the acute pains which 

 are frequently experienced after severe injuries to the head ; a 

 portion of bone, about a centimetre in diameter, being cut out 

 to admit of the introduction of a sponge for the removal of ex- 

 travasated blood. A precisely similar operation is common in 

 Montenegro, where, as at Aures, it is performed by the mem- 

 bers of certain families, amongst whom the profession of tre- 

 phining has flourished for ages, and been respected as an 

 hereditary distinction transmissible from father to son. The 

 author draws attention to the curious circumstance that the 

 practice of trephining and implicit faith in its efficacy have kept 

 their ground, not merely in the semi-barbarous populations of 

 Algiers and the Balkan mountain districts, but even among 

 the miners of Cornwall, who have continued, to our own 

 times, to regard this operation as the only adequate mode of 

 treatment in various injuries to the head. — Contribution to 

 the history of anomalies of the muscles, by M. Ledouble. 

 The author considers that, while the pyramidalis abdomilis, 

 peroneus, palmaris, plantaris, and psoas par\ais are more 

 usually absent than any of the other muscles, the last-named 

 is so frequently missing, that some writers have even assumed 

 that its presence was abnormal. It is more frequent in women 

 than in men ; but for this peculiarity, as well as for the varia- 

 tions observable in the mode of insertion of psoas magnus and 

 parvus, the author does not attempt to offer any explanation : 

 his paper giving simply the result of his own observations of 

 muscular anomalies in the lower animals, as well as in man. 



SOCIETIES AND ACADEMIES 

 London 



Royal Society, November 25. — "On Jacobi's Figure of 

 Equilibrium for a Rotating Mass of Fluid." By G. H. Darwin, 

 M.A., LL.D., F.R.S., Fellow of Trinity College, and Plumian 

 Professor in the University of Cambridge. 



Jacobi was the first to prove that a mass of fluid in the form 

 of an ellipsoid, with three unequal axes, is in equilibrium when 

 rotating about the smallest of the three axes. The determina- 

 tion of the axes in terms of the angular velocity of the system 

 has hitherto been left in an analytical form, not well adapted for 

 numerical calculation. In the present paper the formulje are 

 brought into a shape involving elliptic integrals, and, by the aid 

 of Eegendre's tables, a table of solutions is calculated. 



If (T be the density of the fluid, a the angular velocity, and 

 jTro- the mass, then, when ai74Trir = '09356, the Jacobian ellipsoid 

 is a revolutional figure with axes I-I972, I-I972, o'6977. For 

 smaller values of the angular velocity the first axis increases 

 and the two latter diminish. For example, when a-J^-Kix = 

 •07047, the axes are I'Sgg, o'Sii, 0-694. 



When the angular velocity is infinitely slow, the ellipsoid 

 becomes infinitely long and thin, and tends to assume a figure 

 of revolution about its greatest axis. 



Although the angular velocity diminishes as the length of the 

 ellipsoid increases, yet the moment of momentum continually 

 increases, and becomes infinitely great when the ellipsoid is 

 infinitely long. 



The kinetic energy at first increases with the length, attains a 

 maximum, and then diminishes, so that when the ellipsoid is 

 infinitely long it vanishes. 



The intrinsic energy, however, always increases, so that the 

 total energy of the system has no maximum, and continually 

 increases with the length of the ellipsoid. 



Approximate formulae are given, which assume a very succinct 

 form when the ellipsoids are long. 



December 9. — " A New Method for the Quantitative Estima- 

 tion of the Micro-organisms present in the Atmosphere." By 

 Percy F. Frankland, Ph.D., B.Sc. (Lond.), F.C.S., F.I.C., 

 Assoc. Roy. Sch. of Mines. 



The author commences by describing some of the more im- 

 portant methods which have been elaborated for the bacterio- 

 scopic examination of air. In these he includes the experiments 

 uf Pasteur, Tyndall, Freudenreich and Miquel, Koch, and Hesse. 

 .\fter pointing out the several advantages and disadvantages 

 which attend these processes, he describes a new method which 

 he has devised, in which he has endeavoured to overcome some 

 of the objections to which the others are open. The following 

 is a brief description of the author's method : — 



A known volume of air is aspirated through a glass tube con- 

 taining two sterile plugs, consisting either of glass-wool alone, 

 glass-wool and fine gl.ass-powder, gI.ass-wool coated with sugar, 

 or sugared glass-wool and fine sugar-powder. The plugs are so 

 aiTanged that the first one through which the air is drawn is 

 more pervious than the second. After a given volume of air 

 has been aspirated, the two plugs are transferred respectively to 

 two flasks, each containing melted sterile gelatine-peptone, which 

 are then plugged with sterile cotton-wool stoppers. The plug is 

 then carefully agitated with the gelatine until it has become 

 completely disintegrated, care being taken to avoid any frothing 

 of the gelatine ; and the latter is then slowly congealed so as to 

 form an even film over the interior surface of the flask. 



On incubating these flasks at a temperature of 22° C, in the 

 course of from four to five days the colonies derived from the 

 organisms contained in the plugs make their appearance, and 

 can be readily counted and further examined. A very large 

 number _of experiments are recorded which were made to test 

 the accuracy of the " flask-method." For this purpose experi- 

 ments were made, in which sometimes single, and sometimes 

 double plugs were employed, and it was almost invariably found 

 that all the organisms were deposited on the first plug ; the 

 second plug, in the very exceptional cases when it did yield 

 anything, rarely gave rise to more than a single colony. 



It was also found that, whereas in out-of-door experiments a 

 Itlank Hesse-tube, exposed side by side with the one through 

 which air was being aspirated, contained a number of organisms, 

 — thus creating an important source of error in the quantitative 

 results obtained by Hesse's method, — in the "flask-method" 

 such blank tubes rarely contained any organisms ; and 

 even when such was the case, but a very small proportion of 

 those present in the actual tube. 



This shows that, whereas in Hesse's apparatus any disturbance 

 of the air during the experiment vitiates the accuracy of the 

 result, in the "flask-method" no such effect is produced. 



On the other hand, in the absence of aerial currents, the 

 blank Hesse-tube contained only a few organisms, and a re- 

 markable uniformity was found in the results obtained by Hesse's 

 method and that of the author. This is important, not only as 

 showing the quantitative accuracy of the " flask-method," but 

 in clearly demonstrating that the organisms present in the air 

 exist in an isolulid condition, and not in aggregates, as suggested 

 by Hesse, for it will be remembered that the plug is violently 

 agitated with the gelatine-peptone in the flask, during which 

 operation such aggregates would undoubtedly be broken up 

 wholly or at least partially. It would therefore be reasonable 

 to expect that the "flask-method" would yield a larger number, 

 and possibly a far larger number, of colonies than found in 

 Hes-e's tubes ; but since, on the contrary, the numbers agreed 

 under the circumstances described in so striking a manner, it is 

 shown convincingly that they exist in an isolated condition. 



The paper is illustrated by photographs and drawings. 



