470 



NATURE 



[March 20, 1879 



the eggs in very cold water ; and now experiments made 

 with the same object in view prove that in this respect 

 there is very little, if any, difference in the behaviour of 

 the autumn and spring spawnings. As in the previous 

 experiments eggs artificially fecundated were those opera- 

 ted with, and while some of the eggs were exposed to the 

 salt water at its ordinary temperature at Kiel, others 

 were placed in a wooden refrigerator, into which the 

 same sea-water, but cooled down to the desired degree, 

 was admitted. A most necessary precaution was keeping 

 the eggs from being heaped together, as they then almost 

 invariably became mouldy. Another series of experi- 

 ments was made to test whether the eggs exposed to the 

 very salt waters of the North Sea would ripen quicker or 

 slower than those exposed to the less salt water of the 

 Baltic, but the time of the development, the tempera- 

 ture of the waters being the same, was found to be very 

 slightly, indeed hardly perceptibly different. A third 

 series of experiments were of a very interesting nature, 

 supplementing those already made, as to the rearing of 

 the herring from artificially fecundated eggs. So far as 

 is known, no one has yet succeeded in rearing the 

 young herring, and even Dr. Meyer's repeated attempts 

 broke down, owing to the impossibility of stopping the 

 formation of the hyphae of some fungus, and also in 

 some measure to the difficulty of obtaining suitable food. 

 Very soon after the yolk was altogether consumed they 

 would die, so that most of the experiments on their 

 growth were made on specimens freshly caught from time 

 to time. Once he succeeded, in the spring of 1878, in 

 rearing a few until they attained the size of 72 mm. 

 However, as the result of these experiments, a great deal 

 of insight has been obtained into the food — at first of 

 almost microscopical dimensions — which the young her- 

 ring consumes, and as to the enormous voracity of the 

 little fish. 



Madagascar Forms in Africa. — At a recent meeting 

 of the Society of Naturalists of Berlin Herr Eichler exhi- 

 bited specimens of a new species of Ouviraitdra lately 

 discovered by Herr Hildebrandt in Eastern Africa. The 

 remarkable form of water-plant known as the Lattice-leaf 

 Plant {Ouvirandra fenestralis) with two other species of 

 the same genus have been hitherto regarded as amongst 

 the wonders of the peculiar flora of Madagascar, so that 

 the discovery of a member of the same group in conti- 

 nental Africa is a fact of much importance in botanical 

 distribution. The new Ouvirandra, although agreeing 

 with the Madagascar species in all essential points of 

 structure, does not present the singular holes in the leaves 

 that distinguish the Ouvirandra fenestralis, but one of 

 the other Madagascar species is likewise abnormal in this 

 respect. 



The "Digger" Mollusc and its Parasites.— The 

 little digger, Donax fossor, represents a countless mass of 

 life off Cape May, New Jersey, large areas looking like 

 barley grains lying on a malting floor when the tide 

 retires. It gets uncovered by the breaking surf and 

 instantly reburies itself with its powerful foot when the 

 waves retire. The siphons are long and active, looking 

 like so many Avriggling worms. Although the prey of 

 shore birds and fishes, and beset with parasites, they lie 

 so thick as even to interfere with one another in burying 

 themselves. The liver of these bivalves is always found 

 beset by flukes, from half a dozen to several dozen, and a 

 bell- shaped trichodina crowds the branchial cavity. 



Action of the Heart of the Crayfish. — M. Felix 

 Plateau, of Ghent, has succeeded in applying the graphic 

 method to the study of the heart' s action in the crayfish. 

 A curve is obtained, of which the ascending portions cor- 

 respond to diastole, and the descending to systole, con- 

 trary to what obtains in the vertebrate heart. It is 

 strikingly like the trace of the contraction of a muscle ; 

 a rapid, almost sudden ascent, with a short flat summit, 



then a gradual descent, at first quicker, then slower. This, 

 however, does not represent the whole truth ; it is 

 possible, also, to demonstrate a wave affecting the muscu- 

 lar wall of the heart, and travelling from behind forwards, 

 thus demonstrating that this condensed heart is a true 

 dorsal vessel. On the stimulus of the entrance of reno- 

 vated blood, it is only the hinder half or two-thirds of the 

 heart that contracts immediately. This forces blood into 

 the forward half, which contracts only when the posterior 

 division is again dilating. When the temperature is 

 increased, as a general rule the diastolic phase is abbre- 

 viated, the number of pulsations rising at the same time. 

 M. Plateau has also succeeded in making experiments on 

 the action of the cardiac nerve of Lemoine, an unpaired 

 branch of the stomatogastric ganglion. It is proved that 

 excitation of this nerve quickens the pulsations of the 

 heart, and augments their energy, while section of it slows 

 the heart. Excitation of the thoracic ganglia always 

 retards the heart, the converse of the cardiac nerve. 

 Acetic acid applied to the heart substance arouses its 

 contractions even when they have ceased, and maintains 

 them for several hours. The action of a number of other 

 substances is equally noteworthy, and M. Plateau's full 

 communications to the Acad^mie Royale of Belgium will 

 be awaited with interest by physiologists. 



GEOGRAPHICAL NOTES 



The various geographical journals to hand contain 

 several papers of importance. In the January Bulletin of 

 the Paris Society M. Maunier gives a full and intelligent 

 sketch of geographical work during 1878, while Dr. 

 Harmand gives a brief statement of the results of his 

 recent journeys in Anam. The Paris Society seems to 

 have followed the example set by the London Society, 

 and has introduced a new feature, " Nouvelles," contain- 

 ing notes of geographical work beyond the limits of its 

 own papers. The Zeitschrift of the Berlin Society 

 contains two instructive papers, on the Andamans, by 

 Ad. de Roepstarff, and an account of a journey in south- 

 west Persia, by Dr. A. H. Schindler. In the two numbers 

 of the Verhandlungen of the same society, the last for 1878 

 and first for 1879, the papers of most interest are those 

 on the Mining Industry of Russia, by C. Skalkovsky ; on 

 the latest researches on the Aurora Borealis, by Herr 

 Forster; and on the people of East Africa, by Herr 

 Hartmann. In the Mittheiltin^en of the Vienna Society, 

 No. 2 of this year, Herr Franz Heger gives some hints as 

 to a solution of various geological questions, — glaciation, 

 climate, coal-deposits, &c. — apparently seeking to account 

 for many of the great geological problems by a change in 

 the earth's axis. The March number of Petermann's 

 Mittheilungeti contains several papers of interest. From 

 the journal of a Bremen merchant a narrative is given of 

 a journey up the Jenissei, from its mouth to Jenisseisk, in 

 the summer of 1878; and M. N. Latkin gives a detailed 

 account of our knowledge of the Lena and its basin. 

 Exact news of Nordenskj old's position is given from the 

 San Francisco whaling captain, who was the first to hear 

 of him, and a statement as to the course to be followed 

 by the steamer Nordenskjold, now building at Malmo, 

 and which will start in May, first to succour the Swedish 

 expedition, and then to proceed to the mouth of the Lena. 

 If it cannot return through Behring's Strait, the staff will 

 spend the winter in collecting all possible data in various 

 departments of science. Nos. 3 and 4 of the Bulletin of 

 the American Geographical Society contain, the former 

 a paper by Rear-Admiral Ammer, on the Inter-oceanrc 

 ship canal across the American Isthmus, and the latter an 

 interesting sketch of the life and work of Mercator, by 

 Mr. E. F. Hall. 



News of two African expeditions are to hand, in one 

 case telling of misfortune, and in the other of success. 

 The Belgian expedition, unfortunate from the beginning, 





