502 



NATURE 



[February 8 19 12 



London. 



Royal Socitlv, t-coiu.u) l. — .Sh An nnMMi < .cikU', i\ > . H., 

 president, in the chair. -Dr. A. Harden and Dornthy 

 Norrls : The bacterial production of acttylmcthylcarbinoi 

 and 2 : 3-butylene glycol from various substances, li. lactis 

 aeroficnes and li. cloacae, whr-n j^rown in a peptone solu- 

 tion containing either glucose, Uuvulose, mannose, galac- 

 tose, arabinose, isodulcite, or adonitol, produce both 

 acetylinethyicarbinol and 2 : 3-butylene glycol. Glycerol, 

 ethylene glycol, and acetaidehydf under similar conditions 

 also give rise to butylene glycol in presence of li. lactis 

 acrogenes, but no acetylmethylcarbinol is produced. In 

 these three cases a carbon synthesis is involved analogous 

 to that which occurs in the butyric fermentation of glycerol 

 and lactic acid. The fermentation of citric and malic 

 acids, of dihydroxyacetone, and of peptone w.-iitr ^^ives 

 rise to neither carbinol nor glycol. — J. Thompson : The 

 chemical action of Bacillus cloacae (Jordan) on glucose and 

 mannitol. The B. cloacae, like B. lactis ai-rogencs, pro- 

 duces a considerable proportion of 2 : 3-butylene glycol 

 from glucose and mannitol, as well as a small amount of 

 acetylmethylcarbinol. The other products are alcohol, 

 acetic, lactic, formic and succinic acids, carbon dioxide, 

 and hydrogen. As in the cases of B. lactis aerogenes and 

 B. coli communis, the percentage of alcohol produced from 

 mannitol is about double that formed from glucose. — 

 J. H. Mummery: The distribution of the nerves of the 

 dental pulp. The object of the paper is to demonstrate, 

 with the author's preparations, that the nerve fibres of 

 the dental pulp do not terminate, as considered by most 

 histologists, at the pulp margin, but that, although they 

 here form a narrow plexus, fine neurofibrils pass out from 

 it in great abundance and enter the dentinal tubes, 

 traversing the dentine in intimate association with the 

 dentinal fibriU lo ilie inner margin of the enamel and 

 cementum. 'Wm- bundles of medullated nerve fibres which 

 enter the tooth at the apical foramen traverse the pulp in 

 more or less parallel lines, running in most cases in com- 

 pany with the blood vessels. They send off numerous side 

 branches, which at the periphery of the pulp lose their 

 medullary sheath, the axis cylinders spreading out into 

 a mass of neurofibrils which enter into a more or less 

 dense plexus beneath the odontoblast layer. These neuro- 

 fibrils are more abundant towards the crown of the tooth, 

 and are scattered and nearly absent in the lower part of 

 the root. Fine fibrils are met with in the substance of 

 the pulp, but in much greater abundance at the margins, 

 in the neighbourhood of the odontoblast layer. At the 

 periphery of the pulp these fibres break up into a plexus, 

 known as the plexus of Raschkow, immediatelv beneath 

 the layer of odontoblast cells. From this plexus fine neuro- 

 fibrils pass between and around the odontoblasts, enclosing 

 them in a meshwork and entering into a narrow plexus 

 at the inner margin of the dentine, from which fine fibres 

 are given off to the dentinal tubules. In the substance 

 of the dentine in well-impregnated preparations fine dotted 

 lines can be traced in the tubules. In the major itv of 

 cases there appear to be two fibres in each tubule. These 

 dotted lines can be traced in many preparations to the inner 

 margins of the enamel and cementum. — F. \V. Twort 

 and G. L. Y. Ingrram : A method for isolating and culti- 

 vating the Mycobacterium entcritidis chronicae pseudo- 

 tuberculosae bovis (Johne), and some e.xperiments on the 

 preparation of a diagnostic vaccine for pseudo-tuberculosis 

 of bovines. In iqio the authors demonstrated the possi- 

 bility of obtaining a pure growth of Johne's bacillus on a 

 medium cont;nnin<4 rho powdered substance of th. ,1, ad 

 human tuber( K bacillus. This medium was sui;i;.-i. d bv 

 the possibility that previous failures in attempts to culti- 

 vate the micro-organism of Johne's disease had r. -ulted 

 from an inability on the part of the bacillus to build up 

 some necessary part of its food material, and that this 

 part might be supplied readv formed in the bodies of the 

 dead tubercle bacilli. During the past year the authors 

 have tested the growth of Johne's bacillus on media 

 modified by substituting i per cent, of other dead acid-fast 

 bacilh in place of human tubercle bacilli. Thev have 

 experimented with seventeen varieties, and have obtained 

 positive results with a large number, but negative results 



NO. 2206, VOL. 88] 



with others, including the bovine tubercle bacillus. T) 

 experiments demonstrate a hitherto unrecognised difTer. 

 betw»-on the human and bovine types of tubercle ba> 

 Ihe authors have also succeeded in extracting, by ni' 

 of hot ethyl alcohol and other Milvenls, the <ss<ntial 

 stance (existing in the various acid-fast bacilli) whi« 1 

 needed bv johne's bacillus for its vitality and gro\' 

 The strams of Johne's bacillus which they have isol. 

 have been inoculated into a number of animals, v 

 negative results in the case of rabbits, hens, pig< . 

 guinea-pigs, rats, and mice, thus furnishing further p: 

 that Johne's bacillus is not a variety of the human, bo\ 

 or avian tubercle bacillus. The inoculation of calves 

 a cow with strains of bacilli isolated from cases of ps<-i, 

 tubf'rculous enteritis has reproduced the disease with 

 typical characteristics, and the bacilli have been u^ 

 isolated from the artificially infected areas, and show 

 characters of the bacilli originally inoculated. A\ 

 tuberculin, originally recommended by Hang, of Coji 

 hagen, for the diagnosis of Johne's disease, has in 

 authors' hands given negative results. They have prep, 

 diagnostic and other vaccines from their pure culture'- 

 Johne's bacillus, but so far have been unable to obtain 

 a diagnostic vaccine of sufficient strength. As the bacillus 

 is now growing more vigorously, the authors hope to over- 

 come this difllc'ilty in the near future. — E. A. N. Arber : 

 The fossil flora of the Forest of Dean Coalfield (Glouce«^»' '- 

 shire) and the relationship of the coalfields of the we- 

 England and South Wales. — Dr. F. \V. Edridse-Orecn 

 .Simultaneous colour contrast, (i) The colours and char 

 of colour which are seen on simultaneous contrast api> 

 to be due to the exaggerated perception of objective rel.i' 

 difference of the contrasted lights. Whilst all the kni 

 contrast phenomena are easily explicable on this vie», 

 there are many facts which are opposed to the older 

 theories. For instance, s|>ectral yellow or pigment yellow 

 contrasted with green do not appear red when s 

 through a blue-green glass, which is impervious to the i 

 rays. (2) A certain difference of wave-length is necessary 

 before simultaneous contrast produces any effect. This 

 varies with different colours. (3) A change of intensity of 

 one colour may make evident a difference which is not 

 perceptible when both colours are of the same luminosity. 



(4) Simultaneous contrast may cause the appearance of a 

 colour which is not perceptible without comparison. 



(5) Both colours may be affected by simultaneous con- 

 trast, each colour appearing as if moved further from the 

 other in the spectral range. (6) Only one colour may be 

 affected by simultaneous contrast, as when a colour of 

 low saturation is compared with white. (7) When a fn'^^" 

 estimation of the saturation or hue of a colour has !• 

 made, the contrast colour is considered in relation to 1 

 false estimation. That is to say, the missing (or ad<! 

 colour is deducted from (or added to) both. (8) A comr 

 mentary contrast colour sensation does not appear in 

 absence of objective light of that colour. — Prof. H. 

 Armstrong and E. Horton : Studies on enzyme arti, . 

 XIV. — Urease, a selective enzyme. 



Linnean Society, Januarv 18. — Dr. D. H. Scott, F.K.S., 

 president, in the chair. — Dr. .A. Anstruther Lawrson : 

 Some features of the marine flora at St. Andrews. — Miss 

 E. L. Turner : Discovery of a nestling bittern in Norfolk 

 on July 8, 191 1. Slides were shown from photographs 

 taken by the author, and they showed the young bird in 

 its protective attitude simulating a bundle of reeds, and 

 the nest itself. 



Mineralogical Society, J.Tnuary 23. — Prof W. J. Lew 

 F.R.S., president, in the chair. — Miss M. W. Porter and 

 Dr. -A. E. H. Tutton : The relationship between crystal- 

 line form and chemical constitution ; the double chromates 

 of the alkalies and magnesium. The investigation of the 

 crystals of ammonium-magnesium . chromate containing 

 6H;0, and of those of the analogous salts containing 

 rubidium and cajsium (the formation of the corresponding 

 potassium salt being impossible), shows not only that the 

 double chromates belong to the same monoclinic series as 

 the double sulphates and selenates previously investigated 

 by Dr. Tutton, but that their mutual relationships are 

 precisely parallel to those afforded by the other groups of 

 the series. The rubidium and cjesium salts exhibit the 



