142 



NA TURE 



[June 6, 1907 



lytic enzymes, the one of Uie emulsin or /3-type, the other 

 of the maltaso or o-lypc, and that it is the latter to which 

 the decomposition of phaseolunatin is due, sirice this 

 glucoside is derived from o-dextrose. 



April 18. — " The Fermentation of Glucosides by Bacteria 

 of the Typhoid-coli Group and the Acquisition of New 

 Fermenting Powers by Uacillus dysenteriac and other 

 Micro-organisms." Preliminary communication. By F. W . 

 Twoi-t. Communirated by Dr. Leonard Hill, F.R.S. 



(i) A large number of glucosides may be fermented by 

 many members of the typhoid-coli group of bacteria. The 

 fermentations vary with the micro-organism tested, and 

 the variations are as marked inside each subgroup of 

 bacteria as between adjacent subgroups. 



(2) The sugar-fermenting powers of an organism may be 

 artificially changed by growing the said organism for a 

 succession of generations in media containing a sugar which 

 at the commencement of the experiment it was unable to 

 ferment. 



By this means a pathogenic organism may be altered 

 until it gives fermentative reactions characteristic of a 

 non-pathogenic member of its group. It is possible, 

 indeed, that pathogenic organisms in the typhoid-coli group 

 may so alter their characters that they become unrecog- 

 nisable when growing for some time outside the body in 

 soil, water, &c. If this is so, it might partly account for 

 the difficulty experienced in isolating B. typhosus from 

 these situations. 



It also seems possible that a non-pathogenic organism 

 may lose its fermenting powers and become pathogenic 

 should it find a suitable medium such as the alimentary 

 canal, and regain its old characters when outside the body. 

 This is, however, only a suggestion, which at present is 

 in no way proved. 



In view of the results obtained with the typhoid-coli 

 group of organisms, it seems quite possible that other 

 organisms may show similar changes, and that the ferment- 

 ation tests worked out by Mervyn Gordon for the Strepto- 

 cocci may also be inconstant, if the same means of experi- 

 mentation are employed. 



May 2. — " On the Variation of the Pressure developed 

 during the Explosion of Cordite in Closed Vessels." By 

 Prof. C. H. Lees, F.R.S. , and J. E. Petavel. 



(i) As most of the modern explosives used in ballistics 

 follow the law of combustion by parallel surfaces, it 

 appears from the results described that their properties 

 may be defined by four constants, which may be deter- 

 mined without difficulty by direct experiment. 



(2) The constants b and r (of formula :) fix the maxi- 

 mum pressure which will be attained under any given 

 charging density. The constants a„ and a (of formula2 

 4 and q) measure the rate of combustion and determine 

 the time which elapses between the ignition of the charge 

 and the development of the maximum pressure. 



(3) When the explosive is made up in a cylindrical form, 

 the time occupied by an explosion for the same gravimetric 

 density is proportional to the diameter of the cylinder. 



(4) The rate of increase of the pressure is most rapid 

 when about two-thirds of the maximum pressure has been 

 attained. 



(5) The maximum rate of rise of pressure per second 

 is equal approximately to 1-540 into the square of the 

 maximum pressure in atmospheres divided by the diameter 

 of the cordite in centimetres. 



(6) When the explosion is fired under a high gravimetric 

 density, the " effective " time of combustion may for prac- 

 tical purposes be taken as equal to the time required if 

 the combustion proceeded always at its maximum rate. 



For cordite Mark I. this time is given by T = 36D/P if 

 the diameter D is measured in centimetres and the maxi- 

 mum pressure P in atmospheres, or T = 0'6D/P if the 

 units are inches and tons per square inch. 



Throughout the above investigation the cooling effect of 

 the walls of the containing vessel during the combustion 

 was taken as small enough to be neglected. 



Challenger Society, Mav 3. — Mr. L. W. Byrne in 

 the chair. — Mr. Byrne exhibited and made remarks upon 

 rare deep-water fish of the N.E. Atlantic obtained 

 from various sources. — Dr. Fowler exhibited a new hori- 

 zontal closing tow-net which he had designed for use at 



NO. 1962, VOL. 76] 



different depths down to about 100 fathoms, pointing out 

 that recent work had shown the necessity for a more 

 precise knowledge of the depth at which an organism was 

 captured in the upper zones than was furnished by the 

 ordinary method of open tow-nets of the common surface 

 pattern. — Dr. Fowler also exhibited a new " constant 

 resistance " net, designed to avoid damage to delicate 

 organisms collected for morphological or embryological 

 study ; it was so arranged that the area of the mouth 

 automatically diminishis in proportion as the resistance 

 (pace) increases. 



Royal Meteorological Society, May 15.- Dr. H. R. 

 Mill, president, in the chair. — The standard rain gauge, 

 with notes on other forms ; Dr. Mill. When the late Mr. 

 Symons founded the British Rainfall Organisation forty- 

 seven years ago, such observations as were being carried 

 on were made with rain gauges of the most varied patterns, 

 set up at any height from the ground that suggested itself 

 to the observer, and read irregularly at almost any hour 

 of the day or night. Since that titne there has been a 

 steady approximation to uniformity, and now the greater 

 number of rain gauges in use are of a few definite 

 patterns, set, for the most part, at nearly the same height 

 above the ground. Dr. Mill strongly recommends the 

 .Snowdon pattern rain gauge, which is 5 inches in diameter, 

 has a vertical rim to the funnel of 4 inches, and has an 

 inner. can and also a bottle. He does not recommend rain 

 gauges with shallow funnels, nor the Howard and Glaisher 

 patterns. — .Account of a captive balloon being struck by 

 lightning at Farnborough during a thunderstorm on 

 .\pril II : Colonel J. E. Capper. The lightning flash 

 appeared to travel along the wire until it reached the 

 wagon ; then a sudden bright light appeared and ran 

 right up the wire into the clouds in which the balloon 

 was hidden. The wire was fused, being burnt entirely 

 away where it first touched the iron pulleys which guide 

 the wire when running out. One side of the balloon and 

 net was burnt, probably owing to the hydrogen catching 

 fire, but the other side was uninjured. — A remarkable 

 excavation made by lightning in peat earth on August 2 

 or 3, 1906, in a moorland district of Northumberland : 

 Prof. A. Herschel. — Apparatus for measuring fog 

 densities : J. W. Lovibond. 



Chemical Society. May 16.— Prof. R. Meldola, F.R.S., 

 past-president, in the chair. — The relation between the 

 crystalline form and the chemical constitution of simple 

 inorganic substances : W. Barlow and W. J. Pope. Close 

 packed, homogeneous assemblages made up of two or more 

 kinds of spheres of nearly the same size must approximate 

 in marshalling to holohedral cubic symmetry or holohedral 

 hexagonal symmetry with the axial ratio 0:^ = 1:0-8165. 

 .All the known crystalline forms exhibited by the elements 

 can be interpreted in the light of the above geometrical 

 principles, which also explain how binary compounds com- 

 posed of two elements of the same valency crystallise in 

 the cubic system and how silver iodide crystallises in the 

 hexagonal system. The axial ratios of Csl, and Rbl, 

 are also in accordance with the geometrical principles stated 

 above. — Experimental investigation into the process of dye- 

 ing : J. Hubner. It is shown that the absorption of dyes 

 by cotton and wool is similar in many points to the absorp- 

 tion of these colours by inorganic materials such as 

 graphite and charcoal, and hence it is deduced that dyeing 

 is a purely physical phenomenon. — Esterification constants 

 of substituted-acrylic acids, part ii. : J. J. Sudborougrh 

 and E. R. Thomas. The results illustrate the retarding 

 effect which a double bond in the o/3 position has on the 

 velocity of esterification. — The addition of bromine to the 

 o- and /3-chloro- and bromo-cinnamic acids and their methyl 

 esters : J. J. Sudboroug:h and G. Williams. — The addition 

 of bromine to unsaturated compounds, part i. : J. J. 

 Sudborough and J. Thomas. — Separation of cadmium 

 from zinc as sulphide in the presence of trichloroacetic 

 acid : J. J. Fox. For the complete separation of cadmium 

 and zinc by this means two precipitations are desirable, 

 but this is unnecessary when the proportions of cadmium 

 and zinc are about equal, or when cadmium is present in 

 excess. — The mechanism of bromination of acylamino- 

 compounds. Preliminary notice : J. B. Cohen and W. E. 

 Cross. In the ordinary process of brominating acylamino- 



