57o 



NA TURE 



[April 1 6, i! 



— On the analogy observed by Warming between Koch's comma 

 bacillus and Spirillum fenue, Ehr., by Prof. Leopold Maggi. — 

 On an integer more general than that of living forces, for the 

 movement of a system of material points, by Dr. Giovanni 

 Pennacchietti. — On the psychological action of attention in the 

 animal series (continued), by E. T. Vignoli. — On Grimaldi's 

 proposed agrarian credit to relieve the distress of the Italian 

 peasantry, by P. Manfredi. — Remarks on the legatum optionis 

 of Roman jurisprudence, by Prof. C. Ferrini. — Critical inquiry 

 into the new Italian Penal Code, by Prof. A. Buccellati. — 

 Meteorological observations made at the Brera Observatory, 

 Milan, during the month of February. 



SOCIETIES AND ACADEMIES 



London 



Royal Society, March 19. — "The Paralytic Secretion of 

 Saliva." By J. N. Langley, M.A., F.R.S. 



It has been shown by Claude Bernard and by Heidenhain that 

 section of the chorda tympani nerve on one side, causes a slow 

 continuous secretion from both sub-maxillary glands. Since the 

 secretion which takes place on the side of the body on which 

 the nerve is cut is called the " paralytic " secretion, that which 

 takes place on the opposite side may be called the " anti-para- 

 lytic " or " antilytic " secretion. The author finds that the 

 antilytic secretion becomes slower when the chorda tympani 

 nerve is cut, and stops when, in addition, the sympathetic nerve 

 is cut. It is, then, caused by nervous impulses sent out by 

 a secretory centre in the medulla oblongata. This centre is in 

 a state of increased irritability, for dyspncea causes a much more 

 rapid flow of saliva, and causes it sooner than it does normally. 

 The paralytic secretion during the first day or two of its occur- 

 rence is also caused by stimuli proceeding from the central 

 secretory centre ; since the paralytic secretion is more copious 

 than the antilytic secretion, and since dyspncea causes a greater 

 increase of the former than of the latter, it follows that the 

 increase of irritability in the central secretory centre is greater 

 on the side on which the chorda tympani has been cut than on 

 the opposite side. In this state of increased irritability the 

 central nerve-cells are probably stimulated by the blood supplied 

 to them. The paralytic secretion in its later stages is probably 

 brought about by a similar state of increased irritability in nerve- 

 cells in the gland itself, i.e. of a local secretory centre. In its 

 later stages the secretion continues after severance of all the 

 nerve-fibres proceeding from the central nervous system to the 

 gland ; it is, however, increased by dyspncea, stopped by apucea, 

 and by large doses of anaesthetics, which indicates that it is 

 brought about by nerve-impulses. The peripheral end of the 

 chorda tympani remains irritable for two to three weeks, which 

 is a further indication that the secretory nerve-fibres are con- 

 nected with some, at any 'rate, of the many nerve-cells present 

 in the gland. Notwithstanding the continuous paralytic secre- 

 tion, the gland-cells become slightly more mucous than normal ; 

 except for this and a decrease in size they remain normal. They 

 secrete as usual when the sympathetic nerve is stimulated. 



Geological Society, March 25. — Prof. T. G. Bonney, 

 D.Sc, LL.D., F.R.S., President, in the chair. — Charles De 

 Laune Faunce De Laune and William Hill were elected Fel- 

 lows of the Society. — The following communications were 

 read : — On the relationship of Ulodendron, Lindley and Hutton, 

 to Lepidodendron, Sternberg, Bothrodendron, Lindley and Hut- 

 ton, Sigil/aria, Brongniart, and Rhytidodeitdron, Boulay, by 

 Robert Kidston, F.G.S. — On an almost perfect skeleton of 

 gigas = Rhytina Stelleri {" Steller's sea-cow ") obtained 

 by Mr. Robert Damon, F.G. S., from the Pleistocene peat- 

 deposits on Behring's Island, by Henry Woodward, LL.D., 

 F.R.S., F.G.S. The author spoke of the interest which 

 palaeontologists must always attach to such animals as are either 

 just exterminated or are now in course of rapid extirpation by 

 man or other agents. He referred to the now rapid destruction 

 of all the larger Mammalia, and expressed his opinion that the 

 African elephant, the giraffe, the bison, and many others, will 

 soon be extirpated unless protected from being hunted to death. 

 The same applies to the whale- and seal-fisheries. He drew 

 attention to a very remarkable order of aquatic animals, the 

 Sirenia, formerly classed with the Cetacea by some, with the 

 walruses and seals by others, and by De Blainville with the 

 elephants. He particularly drew attention to the largest of the 

 group, the Rhytina, which was seen alive and described by 



Steller in 1741. It was then confined to two islands (Behring's 

 Island and Copper Island). In forty years (17S0) it was 

 believed to have been entirely extirpated. It was a toothless 

 Herbivore, living along the shore in shallow water, and was 

 easily taken, being without fear of man. Its flesh was good, and 

 it weighed often three or four tons. The author then described 

 some of the leading points in the anatomy of Rhytina, and 

 indicated some of the characters by which the order is dis- 

 tinguished. He referred to the present wide distribution 

 of the Sirenia : — Manatus with three species, namely, M. 

 latirostris, occupying the shores of Florida and the West Indies ; 

 M. americanus, the coasts of Brazil and the great rivers Amazon 

 and Orinoco ; M. senegalensis, the west coast of Africa and the 

 rivers Senegal, Congo, &c. Halicorc, with three species, 

 namely, //. tabernaculi, the Red Sea and east coast of Africa ; 

 H. dugong, Bay of Bengal and East Indies ; H. australis, North 

 and East Australia. The fossil forms number thirteen genera 

 and twenty-nine species, all limited to England, Holland, Bel- 

 gium, France, Germany, Austria, Italy, Malta, and Egypt, and 

 to the United States and Jamaica. The author gave some 

 details as to the dentition of fossil species, of which Halithcrium 

 and Prorastomus are the two most remarkable types. Lastly, 

 with regard toThe geographical area occupied at the present day 

 by the Sirenia, the author pointed out that two lines drawn 30° 

 N. and 30 S. of the equator will embrace all the species now 

 found living. Another line drawn at 6o° N. will show between 

 30° and 6o° N. the area once occupied by the twenty-nine fossil 

 species. He looked upon Rhytina as a last surviving species of 

 the old Tertiary group of Sirenians, and its position as marking 

 an " outlier" of the group now swept away. 



Physical Society, March 28. — Prof. Guthrie, President, in 

 the chair. — The President announced that the meeting on May 

 9 would be held at Bristol ; further particulars would be com- 

 municated to the members. — Mr. Hawes was elected a member of 

 the Society. — The following papers were read : — On calculating- 

 machines, by Mr. Joseph Edmondson. Calculating-machines 

 are of two classes — the automatic and the semi-automatic. The 

 former were invented by Mr. Chaides Babbage between 1820 

 and 1834, and were designed mainly for the computation of 

 tables. The difficulties against which this inventor contended 

 and the perseverance he displayed in the construction of part of 

 the "difference-engine" he had imagined are now a matter of 

 history. On account of the great cost and high degree of com- 

 plexity of this machine it was never completed, and the 

 calculating-machines of the present day belong to the semi- 

 automatic class the first example of which is found in a rough 

 and incomplete instrument by Sir Samuel Moreland in 1663. 

 From 1775 to 1780 the Earl of Stanhope invented machines 

 which were a great advance upon those of Sir S. Moreland. In 

 these is found the "stepped reckoner," the basis of all modern 

 instruments. This "stepped reckoner" was improved by M. 

 Thomas de Colmar, who, in 185 1 produced a machine which 

 is now largely in use. This machine, somewhat improved in 

 detail and construction, is now made by Mr. Tate of London, 

 and Mr. Edmondson has patented a modification in which the 

 form of the instrument is circular, by which means an endless 

 instead of a limited slide is obtained. A collection of various 

 valuable instruments, which had been kindly lent for the occa- 

 sion, were exhibited. A discussion followed in which Gen. 

 Babbage, Mr. Tate, Prof. McLeod, Dr. Stone, the Rev. Prof. 

 Harley, Mr. Whipple, Prof. Ayrton, and other gentlemen took 

 part. — On the structure of mechanical models illustrating some 

 properties in the ether, by Prof. G. F. Fitzgerald. The author 

 had recently constructed and described before the Royal Society 

 of Dublin a model illustrating certain properties of the ether 

 (Nature, March 26, p. 49S). This model was one-dimensional, 

 but the author now showed how a tri-dimensional model might 

 be imagined, though probably mechanical difficulties would 

 render its actual construction impossible. Each element of the 

 ether is to be represented by a cube on each edge of which there 

 is a paddle-wheel. Thus on any face of the cube there will be 

 four paddle-wheels. Now, if any opposite pair of these rotate 

 by different amounts, they will tend to pump any liquid in which 

 the whole is immersed into or out of the cube, and if the sides of 

 the cube be elastic there will be a stress which will tend to stop 

 this differential rotation of the wheels. If however the other pair 

 rotate by different amounts, they may undo what the first pair 

 do, and thus the stress will depend on the difference between 

 the differential rotations of these opposite pairs of wheels. If 

 i) represent the angular rotation of one pair, and C that of the 



