214 



NA TURE 



[January 2, 1896 



which I have attempted to eUicidate in this paper, may be 



summarised as follows : — 



(i) The existence of a very thin membrane, or a structure bf 

 membrane-like appearance, lying between the ameloblasts and 

 the forming enamel, and also between these cells and those of 

 the stratum intermedium. I have also, in many specimens, seen 

 a similar membrane covering the odontoblasts. 



(2) The formation of enamel by deposit, and not by cell cal- 

 cification. This deposit probably consists of two distinct cell 

 products — a granular plasm and spherules of calcoglobulin. 



(3) The relation of the cells of the stratum intermedium to 

 true secreting tissue ; this relation being especially marked in the 

 enamel orj^ans of the rat and mouse. 



(4) An intricate vascular network in the stratum intermedium. 

 I should also mention that I have seen a free distribution of 

 blood vessels in the odontoblastic layer of cells in the mouse, 

 rat, and calf, as well as in human embryos, thus conclusively 

 proving that these cells are not calcified. 



(5) The fibrous character of enamel in many of the lower 

 animals, and the change of these fibres into more or less regularly 

 arranged granules in the monkey and in man. 



(6) That the varicosities of the enamel rods are not caused by 

 acids (although often rendered more clear to view by acid treat- 

 ment), but represent a true structural peculiarity of this tissue. 

 That these varicosities, which often continue in an uninterrupted 

 line across large fields of view, correspond with the course of 

 one set of fibres. The varicosities may, therefore, be caused by 

 the presence of this set of cross fibres. The only alternative 

 explanation which has occurred to me is that there may be a 

 rhythmic, simultaneous action of all the ameloblasts concerned 

 in the deposit of the material for enamel building. The last 

 theory seems to be less reasonable than the first. ^ 



(7) The Retzius bands are often as distinctly marked in form- 

 ing as in mature teeth, and in teeth which have been kept 

 constantly moist, as they are in dried specimens. The enamel 

 rods are often seen to pass without break across several of these 

 bands. The bands are principally due to a deposit of pigment, 

 and not to imprisoned air or gas, as claimed by von Ebner. 



Chemical Society, December, 5, 1895.— Mr. ^- Vernon 

 Harcourt, President, in the chair. — The following papers were 

 read : — Researches on the terpenes, VI. Products of the oxida- 

 tion of camphene ; camphoic acid and its derivatives, by J. E. 

 Marsh and J. A. Gardner. Camphoic acid, CioHi40g, is the 

 chief oxidation product of camphene ; a number of new deriva- 

 tives of the camphopyric acids, C9H14O4, are described.— New 

 derivatives from adibromocamphor, by M. O. Forster. On 

 treating a-dibromocamphor with nitric acid, a lactone, dibromo- 

 campholidid, CjoHj^BrgOg, is obtained ; on reduction it yields 

 an unsaturated acid, bromocamphorenic acid, CioHjjBrOg. 

 Camphorenic acid, CjoHigOj, and campholidid, CioHjgOs, have 

 been prepared. — Isomeric 7r-bromo-a-nitrocamphors, by A. Lap- 

 worth and F. S. Kipping. Tr-bromo-a-nitrocamphor is obtained, 

 together with a bromocamphoric acid, by heating ir-dibromo- 

 camphor with nitric acid ; it is converted into an isomeride by 

 crystallisation from hydrochloric acid. These two substances 

 are probably cis- and trans-isomerides. — Derivatives of 7r-bromo- 

 camphoric acid, by F. S. Kipping. 7r-bromocamphoric acid, 

 when treated with alkalis, yields first a lactonic acid, C10H14O4, 

 and then TT-hydroxycamphoric acid, CjoHigO., ; it probably contains 

 the group CIIgBr. — 7r-dibromocamphoric acid and its derivatives, 

 by F. S. Kipping. 7r-dibromocamphoric anhydride, CjoHigBrgOa, 

 is prepared by the action of bromine and red phosphorus on tt- 

 bromocamphoric acid ; it yields 7r-dibromocamphoric acid, 

 C,QH,4Br204, when heated with nitric acid, and ir-bromocam- 

 phanic acid,CjoHj3Br04 on boiling with water. — w-bromocam- 

 phoric acid, by F.S. Kipping, w-bromocamphoric acid, isomeric 

 with TT-bromocamphoric acid,is obtained by hydrolysing Wreden's 

 bromocamphoric anhydride. — 7r-chlorocamphoric acid, by F. S. 

 Kipping and W. J. Pope. Tr-chlorocamphoric acid, C10H15CIO4, 

 is prepared by oxidising 7r-dibromocamphor with nitric acid. — 

 Derivatives of a-hydrindone, by C. Revis and F. S. Kipping. 

 Dibromohydrindone is obtained by the action of a soda solution 

 of bromine on a-hydrindone at ordinary temperatures, whilst at 

 100° a condensation product of the composition Ci8Hj203 is ob- 

 tained. When monobromohydrindone is dissolved in cold alco- 

 holic potash, a condensation product of the composition 

 CxaHijBrOj is deposited. — The alkaline reduction of metani- 



1 Since the above was written, I have demonstrated that there is a 

 simultaneous deposit of the spherical bodies over the entire surface of 

 forming enamel.— J. L. W. 



NO. 1366, VOL. 53] 



traniline, by R. Meldola and E. R. Andrews. Alkaline reducing 

 agents convert metanitraniline into an azoxy-compound, 

 NH2.C6H4.N. 



• /O ; the corresponding azo-compound has also 

 NH,.CgH4.N/ 



been prepared. — The chemistry of dibromopropylthiocarbimide ; 

 and the action of bromine and iodine upon allylthiourea, by A. 

 E. Dixon. 



Linnean Society, December 5, 1895.— C. B. Clarke, P'.R.S., 

 President, in the chair. — Messrs. Bernard Arnold and Rupert 

 Vallentin were admitted, and the following were elected Fellows 

 of the Society : W. M. Christy, Rev. H. P. Fitzgerald, A. W. 

 Geffeken, Rev. E. A. Peacock, Rev. T. R. Stebbing, and W. O. 

 Stentiford. — The President called attention to a portrait of the 

 late Prof. Babington, of Cambridge, which had been lately pre- 

 sented by his widow to the Society. On the motion of Dr. 

 Murie, seconded by Mr. A. W. Bennett, a vote of thanks 

 to Mrs. Babington was unanimously accorded. — Prof. Stewart 

 offered some remarks on the types of the axes of certain 

 Gorgonacese, in which he referred chiefly to the importance or 

 otherwise of the presence of spicules in the axes, and exhibited 

 the following species in illustration of his remarks : Paragorgia 

 arborea, Melitodes ochracea, Siiberogorgia suberosa, Coralliitm 

 riibrmn, Caligorgia verticillata, Verritcella gitadahtpensis , his 

 hippiiris, Pkxaiirella crassa, and Eunicella verrticosa. Some 

 criticism was offered by Dr. Murie, chiefly in relation to the 

 structure of Gorgonia flabelliini and Gorgonia setosa. — -Mr. Martin 

 Woodward exhibited and made remarks on a living specimen of 

 Otira??iaba, which he thought should be regarded as a common 

 Amoeba attacked by a parasitic fungus. — Mr. G. C. Druee com- 

 municated a paper on a new species of Bromus in Britain, which 

 was said to differ from others of the genus in its inflorescence, 

 having single, short, stiff pedicels arising alternately right and 

 left of the main rachis, each bearing at its extremity 3-5 sessile, 

 or in some cases shortly stalked spikelets, giving an interrupted 

 and compact appearance to the whole inflorescence, which is 

 made up of two rows of clustered groups of 3-5 spikelets. This 

 peculiar feature being absent in its nearest allies, the name 

 interruptus was proposed to distinguish it ; another feature 

 being that the palea was split to the base, and not 

 merely bifid. It appeared to have been described or re- 

 ferred to by Prof. Hackel as Brotmis mollis, var. inter- 

 ruptus, but Mr. Druce considered that it was sufficiently 

 distinct to be entitled to specific rank. He had found it grow- 

 ing abundantly in a field of vetches near Upton, Berkshire, and 

 specimens had been examined from Headington, Oxford, and 

 Dartford, Kent. In a discussion which followed, Dr. O. Stapf 

 reviewed the literature of the subject, and gave reasons for 

 regarding the so-called new species as merely an abnormal 

 growth of Bromus mollis. Critical remarks were made also by 

 ^Ir. H. Groves and Mr. A. B. Rendle, who were inclined to 

 share the opinion of the last speaker.— A paper was then read 

 by Mr. W. F. Kirby, on some new or little-known Fhasmida in 

 the collection of the British Museum, with illustrative specimens. 



Mathematical Society, December 12, 1895.— Major P. A. 

 MacMahon, R.A., F.R.S., President, in the chair.— Prof. 

 Hill, F.R.S., gave a sketch of a note on the convergency of 

 series, by Dr. R. Bryant. — Lieut. -Colonel Cunningham, R.E., 

 communicated at some length a paper on the criterion of 2 as a 

 16''^ residue. A discussion followed the reading, in which 

 Messrs. Bickmore, Kempe and the President took part. — Dr. 

 Hobson, F.R.S., read a short note on the distribution of electri- 

 city induced on an infinite disc with a circular hole in it, by Mr. 

 H. M. Macdonald.— A paper by Dr. R. Lachlan, on the 

 double foci of a bicircular quartic, and the nodal focal curves of 

 a cyclide, was taken as read. 



Zoological Society, December 17, 1895. — Sir W. H. 

 Flower, K.C.B., F.R.S., President, in the chair.— Dr. 

 Donaldson Smith offered some remarks on some of the animals 

 observed by him during his recent journey to the Lakes 

 Rudolph and Stephanie, and alluded especially to the species of 

 zebras and antelopes encountered during his journey. — Mr. 

 Sclater exhibited and made remarks on the head of an antelope 

 obtained in Kavirondo, British East Africa, by Mr. E. Gedge. 

 This antelope had been hitherto usually identified with the 

 " kob " of Western Africa, but appeared to belong to a distinct 

 species, to which the name Cobus thomasi had been given by 

 Herr Neumann. — Mr. G. F. Hampson read a paper on the 

 classification of two sub-families of the moths and of the family 



