ii8 



NATURE 



\_Nov. 29, I 



Bleeding has a similar effect to dyspna-a and to clamping 

 the carotid, but its most marked effect is an increase in the 

 percentage of organic substance. 



Injection of dilute salt solution, NaCl, o'2 to o"6 per cent., in 

 sufficient quantity, considerably increases the rate of secretion of 

 saliva ; the percentage of salts in the saliva decreases, although 

 the rate of secretion of salts usually increases ; the percentage of 

 organic substance decreases ; that is, increasing the volume of 

 the blood with dilute salt solution chiefly increases the rate of 

 secretion of water. 



Injection of strong salt solution increases the percentage of 

 salts in saliva. This is in accordance with the recent observations 

 of Novi, that the chlorine in the salts of saliva is increased for 

 a given rate of secretion by inci-easing the percentage of sodium 

 chloride in the blood. 



Saliva produced by stimulating the chorda tympani, or by in- 

 jecting pilocarpine, after a small dose of atropine has been given, 

 contains a low percentage of organic substance and of salts. 



The authors, like Werther, find that sub-lingual saliva has a 

 considerably higher percentage of salts than sub-maxillary 

 saliva. 



If lithium citrate, potassium iodide, potassium ferrocyanide, 

 and pilocarpine are injected into the blood, lithium can be detected 

 in the first drops of saliva secreted, potassium iodide after the 

 first six drops ; potassium ferrocyanide cannot be detected at any 

 stage of secretion. 



The general result of these experiments is to show that the 

 secretion of water, of salts, and of organic substance are dif- 

 ferently affected by different conditions, and that the percentage 

 composition of saliva is determined by the strength of the stimulus, 

 by the character of the blood, and by the amount of blood 

 supplied to the gland. 



All, or nearly all, the arguments which have been adduced to 

 prove that the secretion of organic substance is governed by 

 special nerve -fibres, have their counterparts with regard to the 

 secretion of salts, so that we might imagine at least three kinds 

 of secretory fibres to be present. The experiments, on the 

 whole, indicate that this complicated arrangement does not exist, 

 but that the stimulation of a smgle kind of nerve-fibre produces 

 •varying effects according to the varying conditions of the gland 

 cells. 



Linnean Society, TJovember 15; — Mr. W. Carruthers, 

 F.R.S., President, in the chair. — On behalf of Mr. H. Bolus, 

 Mr. J. G. Baker exhibited a specimen of £nVj-/«-w«w /f/zV/^ 

 fentm, a plant showing a very remarkable type of leaf- structure. 

 It was figured by Andrews in his "Botanist's Repository" in 

 1807, and lost sight of until recently refound by Mr. Bolus in 

 Namaqualand.- — Prof. Stewart exhibited a substance which had 

 been picked up on the sea-shore, the nature of which it had 

 puzzled many to determine, its structure being regarded ;by 

 some as animal, by others as vegetable. He proposed to submit 

 it to careful microscopical examination.— Mr. J. E. Harting 

 exhibited a South American bat from Trinidad {JVociiiij 

 leporinns), alleged to be of piscivorous habits, and remarked 

 upon a similar habit which had been observed in a species ot 

 Ptcropus in India; — A paper was read by Mr. B. D. Jackson, on 

 behalf of Mr. H. Chichester Hart, on the mountain range of 

 plants in Ireland, and was criticized by Mr. J. G. Ilaker, who 

 gave an interesting sketch of the characteristics of the .Irish 

 flora. — Two papers were then read, by Mr. Sladen, on the 

 mammals and birds collected by Mr. H. K. Ridley in 

 Fernando Noronha, in the determination of which the. author 

 had been assisted by Mr. O. Thomas .and Mr. R. 'iS. Sharpe. 



Physical Society, November 10. — Prof. Reinold, President, 

 in the chair. - The following communications were read : — On 

 the calculation of the coefficient of mutual induction of a helix and 

 coaxal circle, by Prof. J. V. Jones. In arranging some experi- 

 ments for determining resistance absolutely by Lorenz's method, 

 the author had occasion to consider what form of standard 

 coil was most suitable for accurate calculation, and chose a helix 

 of large diameter with a single layer of wire. To obtain a suffi- 

 cient number of turns requires considerable axial length, and 

 Lord Rayleigh's approximate method of calculating the co- 

 efficient was -found to be insufficient where an accuracy of 

 i/ioo per cent, is required. A method of calculation is given 

 considering the wire as a helix whose equations are^' = A cos 0', 

 z' = K sin &, and x' = M, those of the circle beingjf' = a cos 6 

 and z = a sin 6. Applying the formula obtained to a cirdle 

 of 10 inches diameter placed concentric with a hdix of 



20 inches diameter and 4 inches long, the value obtained is 

 M = « . 53'259, whereas Lord Rayleigh's formula gives 11 . 53 '3 17. 

 Dr. Fleming described a wooden anchor ring wound like a 

 gramme armature, and having a secondary coil ad,ded, which he 

 had devised as a standard of mutual induction," and used for 

 determining capacity absolutely. In reply, the author said he 

 had not considered the wire to have thickness, as he felt sure 

 this would not affect the result for his coil by one part in 

 icx),ooo. With respect to Dr. Fleming's anchor ring, he con- 

 sidered the difficulty of winding it sufficiently uniformly to be a 

 great drawback to its general adoption.— On the upper limit of re- 

 fraction in selenium and bromine, by Rev. T. Pelham Dale, read 

 by Mr. Baily. In a former paper (read February 11, 1888) the 

 author showed that an upper limit of refraction for selenium 

 should theoretically exist about the middle of the visible spec- 

 trum, and the present communication describes some experi- 

 ments which tend to confirm the prediction. On placing a thin 

 film f of selenium under a spectro-microscope, it was found to 

 be opaque to rays above the green, and previous calculation 

 had given 52957 as the limiting wave-length transmissible. 

 Sulphur at ordinary temperatures should have its upper limit 

 beyond the visible spectrum, but theory indicates that increased 

 temperature will lower the limit. It is well known that sulphur 

 darkens when heated, and when a film of boiling sulphur was 

 examined under the spectro-microscope, all but the red end of 

 the spectrum was absorbed. On cooling, the region of absorp- 

 tion gradually retreated towards the violet end. Selenium is 

 also found to become more transparent as it is cooled, and its 

 refractive equivalent is equal to that of sulphur multiplied by the 

 ratio of its chemical equivalent to its density. Important optical 

 as well as chemical relations thus exist between the two elements. 

 The results obtained by bromine films were remarkably similar 

 to those of selenium, the violet rays being entirely cut off. A 

 method of solving the equation a sin 6 = sin m& (on the limiting 

 solution of which the upper limits of refraction depends), by a 

 table of Eulerian integrals, is given in the paper, and an analogy 

 between total reflection and the upper limit of refraction is 

 traced. — Experiments on glass in polarized light, by Prof. S. P 

 Thompson. — On a new form of standard resistance coil, by Dr 

 J. A. Fleming. 



Chemical Society, November i. — -Mr. W. Crookes, F.R.S., 

 President, in the chair. — The following papers were read : — 

 The constitution of the terpenes and of benzene, by Prof. W. 

 A. Tilden, F.R.S. When oxidized under similar c inditions 

 with dilute nitric acid, the natural terpenes— australene, 

 terebenthene, and hesperidene— yield less than 2 per cent., 

 dipentene (terpilene) yields 27*6 per cent., and cymene and 

 paraxylene yield 73 to 80 per cent, of paratoluic acid. Each of 

 the four terpenes combines with two molecular proportions of 

 bromine, and no more. Camphene, however, does nat combine 

 with bromine, and hence must be regarded as saturated in the 

 usual sense. The author concludes that since the terpenes con- 

 tain at most four units of available combining capacity, the 

 nucleus of six carbon atoms which they all undoubtedly contain 

 must be united into a closed chain containing at the most two 

 double "bonds." Kekule's benzene formula is a well-known 

 representation of a ring of six carbon atoms, but must be aban- 

 doned, since the author considers that the terpenes are certainly 

 not benzene derivatives. Kekule's formula is open to the objec- 

 tion that it represents benzene as containing " ethylenic " carbon, 

 for which there is no evidence at all. Moreover, a body of this 

 formula, when treated with nitric acid, ought to yield abundance 

 of oxalic acid. This the terpenes do, but the benzenoid hydro- 

 carbons do not. Referring to this last statement. Dr. Japp, 

 F.R. S., said that phenol on oxidation with alkahne perman- 

 ganate gave a considerable quantity of oxalic acid ; Mr. Groves, 

 F.R.S., added that oxalic acid is obtained in quantity on 

 oxidation of chloranilic acid ; and Dr. Perkin, F.R. S., remarked 

 that he had obtained a quantity of oxalic acid in preparing picric 

 acid from phenol. Dr. Perkin also said that the low magnetic 

 rotatory power of American turpentine was a probable indication 

 of the non-existence of a nucleus of six carbon atoms. Mr. 

 Wynne remarked that the production of o-naphthol by the 

 distillation of phenylisocrotonic acid, a compound in which 

 " ethylenic " carbon was undoubtedly present, might be quoted 

 in support of Kekule's benzene formula ; and Prof. Armstrong, 

 F.R.S. , expressed the opinion that the evidence at disposal was 

 entirely insufficient to enable us to determine the constitution of 

 the terpenes with any degree of probability. — Some new com- 

 pounds of magnesia with the halogens, a contribution to the 



