46 



NA TURE 



{Nov. 



ciated the volume of the sarcoglia, whose existence is thereby 

 shown, and which rivals that of the rhabdia, we might have 

 studied this component of muscle in its physiological relations 

 to contractility, as well as in its morphologicil and genetic 

 relations, which are the only ones yet known. 



If now, in many cases, it appears that the nerve comes in 

 contact only with the surface of a thick layer of sarcoglia, while 

 the rhabdia everywhere is covered by very fine layers of the latter, 

 whose absolute absence in the field of innervaiion can nowhere 

 be demonstrated, we have to conclude that in general the nerve 

 does not act directly upon the rhabdia, but only on the sarcoglia. 

 This at once gives the latter a physiological interest. We have 

 to ask whether the glia is the medium that conducts the stimulus 

 between nerve and rhabdia, or whether it is itself the contractile 

 element, while the rhabdia has a signification other than that 

 formerly attributed to it when we were completely ignorant of 

 the glia. 



All contractile substance requires the co-operation of an 

 elastic element. Where is this to be found in the muscle fibre? 

 The envelope of the sarcolemma, which is certainly elastic, but 

 delicate, and whose mass is almost infinitesimal compared 

 with that of the muscle -fibre, cannot satisfy the requirement ; 

 but more solid structures freely distributed in the paste-like 

 sarcoglia could perhaps do so, and such we find in the rhabdia, 

 in the form of prismatic particles, ranged with such constancy 

 and with such regularity longitudinally and transversely, that we 

 may hold them to be the elastic element. Then the sarcoglia 

 would become the contractile element, and the nerve would have 

 an easier task. 



I could wish that this view Vnight be accepted as an hypothesis. 

 As far as 1 can see, it does not contradict experience, for it only 

 puts back the muscle nearer to the protoplasm and to all that is 

 contractile, and so far coincides with experience that we find 

 muscles in the same measure less elastic and more sluggish in 

 protoplasmic movement the richer they are in sarcoglia, as in 

 the case of the led muscles, nucleated and rich in glia, which 

 contract more slowly but with greater power than the white 

 muscles, poorer in glia, which are quick and spring-like, and also 

 the sluggish embryo muscles, in which glia predominates be- 

 cause as yet but little protoplasm has been converted into 

 rhabdia; and further the cells of unstriped muscle-fibre, which 

 are wanting in the regular transverse striation, and contain, as 

 it appears, besides more abundant glia, an elastic material of 

 special form and arrangement. 



The hypothesis would be overthrown if contractile fibrils were 

 found in which no sarcoglia was to be detected. But even in 

 the finest fibrils of Steiitor, the structure of which Biitschli ^ has 

 recently elucidated, we must hold the significance of punctated 

 transversely penetrating indentations to be protoplasmic, and 

 we can therefore scarcely expect ever to find a contractile thread 

 in which nothing whatever should be found of the primitive 

 contractile material such as it everywhere exists. 



Of late, this view - has been defended from the purely morpho- 

 logical side,^ on the strength, namely, of the very fine reticular 

 structure of protoplasm to which more attention is being paid, 

 and which is demonstrable on objects of all grades of organiza- 

 tion. Protoplasm, in fact, is not so formless as at first appeared, 

 but shows a structure comparable with nothing better than with 

 the appearance presented by a transverse section of muscle with 

 its glia framework stained with gold. We may expect that 

 these reticular structures, whose consistency appears to vary 

 extraordinarily, will some day lead to the establishment of a 

 fruitful hypothesis of the inner mechanism of protoplasmic 

 movement, in place of that held hitherto, which affoids no 

 glimpse into the essence of vital mechanical work. 



Compared with this larger problem, that of the causation of 

 vital movement appears the more accessible of the two, the 

 latter being considered as a physiological inquiry after the con- 

 stitution of the normal stimulus by which work is done. 

 Perhaps, indeed, the answer is to be looked for from the most 

 perfected organization of muscle, where the iniatory process is 

 localized by a distinct nerve-ending, rather than from the 

 primitive organization, where the excitation may set in at any 

 place, and lies in the protoplasm itself. We know distinctly 

 that the muscle-wave begins in the field of innervation, for we 



' '■ Dr. H. G. Bronn's Classen und Ordnurigen des Thierreiches," neu 

 bearbeitet von O. Biitschli, Leipzig und Heidelberg, 1888, vol. i. p. 1298. 



^ Kuhne, "Neue Unlersuchungen Uber motorische Nervenendigung," 

 ZW/itA>- i>'/W. , vol. xxiii. pp., 88-95. 



3 A. van Gehuchten, "Etude sur la structure intime de la cellule 

 muBculaire striee," La Cellule, vol. ii. p- 289. 



have long seen the natural contraction in the interior of trans- 

 parent insect larvrc starting from the nerve-eminences. We 

 know this also from the experiments of Aeby, who followed the 

 muscle-wave myographically from the nerve-line onward, and 

 now we are able to display the laeginnings of the contraction 

 as local thickenings at the point of attachment of the nerves 

 caught and fixed by sudden hardening. Since the nerve grasps 

 the muscle in a restricted region, it expends its action upon this 

 exclusively ; that which follows on as muscular activity is the 

 nerve's work no longer. 



Galvani and his successors for more than a century suspected 

 that nervous forces were electrical, and, in reality, the celebrated 

 champion of electro-physiology in our day has been able with 

 the galvanometer tc render the excitation of nerves, unattached 

 to muscles or ganglion-cells, evident as the negative variation of 

 the natural nerve-current, to cause movement of a magnetic 

 needle instead of a muscle, or to put the needle in the place oi 

 sensa'ion. After this no consideration of the nature of nervous 

 activity is conceivable which does not take into consideration 

 this discovery of du Bois-Reymond's — least of all where the 

 nerve has to excite something with which it is not fused, like 

 muscle, but which it only touches, and that not directly, while- 

 still invested by the axolemma. Only during excitation, as 

 Ludimar Hermann has taught us, are electric currents issuing 

 fro.n the nerve through its conducting surroundings, in which the 

 course of these currents of action is to be estimated from the 

 duration of the negativity of the nerve-tract excited, and from 

 the speed of propagation of the nerve-wave, if we know tlie 

 conductor and the disposition of the nerve. The motor endiny; 

 fixes the latter, and so peculiarly that we can only presuppose 

 from it a furthering of the excitor effects of the currents ol 

 action. 



The currents of action of muscle, whose electromotive be 

 haviour agrees so wonderfully with that of nerve, have loni; 

 been proved to produce excitor effects, although only powerful 

 enough to act upon nerves ; but there are also, under certain 

 conditions discovered by Hering, such effects from nerve tc 

 nerve. ^ Is the possibility, we may hence ask, to beexcluded, ol 

 one muscle exciting another, and is it quite impossible that r 

 nerve only throws a muscle into contraction by means of it 

 currents of action ? 



The first question we can answer. I will do so by a simple- 

 experiment. Two muscles, the nerves of which are disposed ot 

 by poisoning with curare, need only to be pressed together 

 transversely over a narrow area to make a single muscle ot them 

 of double length, in which the stimulation and contraction arc 

 propagated from one end to the other. Since the transference 

 from one muscle to the other is done away with as soon as we 

 bring the finest gutta-percha between the muscles as an insulator, 

 or gold-leaf as a secondary circuit, the first muscle must have 

 excited the second electrically. ^ 



THE ASTRONOMICAL OBSERVATORY OF 

 PEKIN. 

 T N the course of a lecture delivered before the Pekin Literat7 

 Society, on the Astronomical Observatory of the Chinese 

 capital, Prof. Russell said that it is the oldest in the world. 

 The oldest in Europe is that of Denmark, founded in 1576 by 

 Frederick 111., at which Tycho Brahe made his famous obser- 

 vations. The Royal Observatory at Paris was not opened till 

 1671, and that of Greenwich three years later. The Pekin 

 Observatory was established in 1279, in the reign of Kublai Khan, 

 the first emperor of the Mongol dynasty, and three of the 

 original instruments yet remain. In 1378, these instruments were 

 probably used in observing Halley's comet, and they will be used 

 twenty-two years hence to witness its next return. If the visitor 

 enters by a door in the south wall of the Observatory, he comes 

 into a court running east and west. In this court are kept the 

 three original instruments. Tnere were four at one time, but the 

 fourth, a celestial globe, has disappeared. Kuo Shouching, 

 a Chinese astronomer, who flourished in the reign of Kublai 

 Khan, was the maker of these. Before their construction, bronze 

 astronomical instruments, which were made about the year 1050, 

 were used, first at K'ai Feng Fu, the capital of Honan, whence 

 they were removed to Pekin. Kuo Shouching found these 



' Sitzber. derk. Akad. zu IVien, vol. Ixxxv. Abth. 3, 1882, p. 237. 

 I " Kiihne, '"Secundare Erregung vom Muskel lura Muskel, Zettschr, 

 I Biol., vol. xxiv. p. 383. 



