Au^. 26, 1875] 



NA TURE 



^l 



These are greatly at variance with the positions ob- 

 served, which show that the companion was then in the 

 following semi-circle, arcl by the estimates of distance had 

 approached the primary bttween 178 land 1802. Barclay's 

 epoch i87r4 assigns a distance less by o"35 than was 

 observed at Leyton in 1866, which is confirmed by Dem- 

 bowski's measures about the same time. There is in the 

 case ofihis star a very unusual discordance bttAcen the dis- 

 tances of Struve and Dawes, which attains a maximum, 

 o"*45, about 1836-5 ; in deducing the above formuire 

 Stiuvc's measures were employed. The rate of increase 

 in the distance has been diminishing, until by Dem- 

 bows.ki's measures, 1863-68, it was less than o"oi 

 annually ; the orbit is evidently inclined only a few 

 degrees to the line of sight, s^o that the companion made 

 a very close approach between 1802 and 1819. — If the 

 anf^les of position, in thef case of 2 1819 between 1828 and 

 1870 are projected, it will appear that the velocity has 

 been diminishing from about 2'''i in 1840, to ©'^■85 at the 

 end of the period, which with the accompanying mcrease 

 of distance confirms Struve's judgment as to orbital 

 motion ; there is already a diminution of angle of nearly 

 70*^ since the first Dorpat measures. — It n,ay be hoped 

 that 2 2107 has not been forgotten this year. 



M. Leverrier's Theory and Tables of Saturn. — 

 We learn that M. Leverrier has completed his long- 

 continued and exhaustive investigations on the motion of 

 Saturn, and tbat his theory is nductd into tables, which 

 will of course speedily take the place of those of Bouvanl, 

 or of provisional tables which have been used m the pre- 

 paration of one or two of our ephemeridei:, pending the 

 publication of others founded upon a more complete 

 theory and discussion of the observations from ihe tmie 

 of Bradley. As in all Leverrier's previous researches of a 

 similar nature, he has made use of the rich store of 

 observations accumulated at the Royal Observatory, 

 Greenwich during upwards of 120 years, and also of the 

 long series which has been formed at ihe Observatory of 

 Palis. The mathematical astronomer will await the pub- 

 lication of M. Leverrier's researches in detail with extreme 

 interest. The Tables of Saturn are understood to be 

 necessarily of considerable extent, with the view to their 

 convenient application. 



The Great Comet of 1819.— The parabolic orbits so 

 far coinputed for this comet, which was observed from the 

 beginning of July to the middle of October, do not repre- 

 sent the observations with sufficient precision, and it is 

 probable that no parabola will be found to do so. The 

 following may, perhaps, be closer than any yet pub- 

 lished : — 



Perihelion passage 1819, June 27.71547, Greenwich M. T. 



Longitude of perihelion ... 287° 8' 11" ) Mean equinox 

 Ascending node 273 41 57 \ July o 

 Indinaiion ... 80 44 38 



Log. perihelion distance ... 9 '533233 



Ileliocentiic niolion direct. 



But this orbit exhibits differences from the observations 

 of a kind that should probably be attributed to deviation 

 from parabolic motion, and as we are in possession of 

 many of the original observations, it would be desirable 

 to discuss them with the view of determining the true 

 character of the orbit in which the comet was moving. 

 Its transit over the sun's disc, a nearly central transit, 

 early on the morning of June 26, and the suspicion that 

 it was actually observed upon the disc by Pastorff at 

 Buchholz, or, as is even more probable, by Stark at Augs- 

 burg, give it a peculiar interest. The diagram of the 

 comet's path across the sun, which appears in the 

 "Berliner Astronomisches Jahrbucb," is erroneous; it 

 would pass in greater longitude than that of the sun's 

 centre, as indicated by the above elements, which in this 

 respect are confirmed by the orbits of Nicolai, Dirksen, 

 and Cacciatore. For the centre of the earth the ingress 

 took place June 25 at i6h. 52m'9 mean time at Green- 



wich, 172*^ from the sun's north point towards the east 

 (direct image), and the egress at 2oh. 29m-9, about 9" 

 irom the same point to the east. For the time of transit 

 the elements, no doubt, assign the comet's position within 

 15" or 20", The larger differences from observation are 

 in August. 



SCIENCE IN GERMANY 

 {From a German Correspottdnit.) 

 T N continuation of the previously reported investigations 

 -»■ of the formation of cells in the ovum, we may mention 

 some observations of Kupfifer, which relate to a hitherto 

 rather unknown yet doubtless very widely spread structure 

 of the animal cell. (' On the differentiation of protoplasm 

 in the cells of animal tissues," from " Schriften des natur- 

 wissenschafi lichen Vereins fiir Schleswig Holstein," Hefr. 

 iii. ; and " The salivary glands of Pcriplatieia orientalis 

 and its nervous system," from " Britrage zur Anatomic 

 und Physiologie, als Festgabe Carl Ludwig zum 15 Oct. 

 1874, gewidmet von seinen Schiilern.") Kupffer first dis- 

 covered that the body of the cells from the liver of a fro?, 

 which coat the b liary vessels, consists oi tvvo substances 

 which chemically and physically are widely different, 

 while hitherto it had been considered homogeneous 

 throughout and had been calld protoplasm. A h>alino 

 ground substance (Paraplasm) gives to the body of tiie 

 cell its relatively firm exterior shape, while in its interior 

 a moveable, grained protoplasm is found in varviii,'^ 

 arrangement. It appears as a central mass roiind 

 the nucleus, from which ramified or reticular thread, 

 radiate to ihe exterior side of the liver-cell:^ which is turned 

 towards the blood-vessels, or to that which borders the 

 biliary vessels. From this arrangement of the proto- 

 plasm, which slowly flows in the well-known manner, 

 Kupffer surmised that these were the ways in whicli 

 certain matters were conveyed from the blood into the 

 biliary vessels ; and he found his opinion confirmed 

 when he introduced soluble colouring matter into the 

 blood of the living animals. As the colour entered 

 through the liver-cells into the biliary vessels, it indicated 

 its course through the cells in most cases in exactly the 

 same way in which formerly the protoplasm proper had 

 been found arranged. Similar facts weie found in respect 

 to the liver and kidneys of other Vcrtebrata, in the young 

 back-teeth of calves, in certain glands of insects (Mal- 

 pighian bodies). In the salivary glands of the well- 

 kiiOArn " black beetle " {Pcrtp/ane^a), Kupffer not only 

 found a very soft net of protoplasm-threads inside the 

 ground-substance of the cells, but he also proved their 

 connection with nerve ends. This likewise supports the 

 view that the substance of the animal cell is differen- 

 tiated in a manner similar to that of the vegetable cell, 

 viz., that it consists of an active material which remains 

 moveable and fulfils the special physiological functions 

 of the single cell (protoplasm), and of a more passive 

 material which forms a sort of protecting receptacle, as 

 it were, for the tender protoplasm (Kupffer's paraplasm). 



The "Archiv fiir mikroskopische Anatomic," edited by La 

 Valette St. George and Waldeyer, has produced the follow- 

 ing papers in its eleventh volume, up to this date :— Part I. 

 On Radiolaria and fresh-water Radiolaria-Rhizopoda, by 

 Greeff. — On bone growth, by Strelzow. — Researches on 

 the physiology of the kidney?, by Wittich. — Studies on 

 Rhizopoda, by F. E. Schulze. — Researches on the gan- 

 glion globules of the spinal ganglia, by Arndt. — On 

 Heitzmann's hjematoblasts, by Neumann. — On tissue 

 cells by Waldeyer. Part II, The Ventriculus terminalis 

 of the spinal marrow, by Krause. — Remarks on the 

 nerves of dura mater, by Alexander.— Studies on the 

 development of bones and of bone-tissue, by Stieda. — On 

 the peripherical part of vertebra?, by Ehrlich. — The peri- 

 vascular lymph-spaces in the central nervous system, and 

 in the retina, by Riedel.— On cement layers in the tissues 



