supplying a constant stimulation-the rhythm being supposed due to the same causes as is the artificial rhythm of Aurelia aurita. From this it will be seen that the essential point of difference between the current theory of rhythm as due to ganglia and the theory now proposed consists in this-that whereas both theories suppose the accumulation of energy by ganglia to be a continuous process, the resistance theory supposes the discharge of this accumulated energy to be intermittent, while the exhaustion theory supposes it to be continuous. According to the former theory, therefore, the rhythm results because the stimulation is periodic; according to the latter theory, the rhythm results because the alternate process of exhaustion and recovery, or the fall and rise of excitability, is periodic. Without waiting to discuss the à priori merits of these rival theories, the author proceeded at once to mention some further experiments which were designed to test the new theory, and which have so far confirmed it as to show the causes which modify the natural rhythm of Aurelia likewise modify, in the same ways and degrees, the artificial rhythm. (a) Other modes of constant stimulation, besides that supplied by faradaic electricity, likewise cause rhythmic action on the part of the deganglionated tissues of Medusa. For instance, the voltaic current causes this action*; and dilute chemical stimuli tend to produce the same effect. (b) With each increment of temperature the rate of the artificial rhythm increases suddenly, just as it does in the case of the natural rhythm. Moreover, there seems to be a sort of rough correspondence between the amount of influence that any given degree of temperature exerts on the rate of the natural and of the artificial rhythm respectively. Further, it will be remembered that in warm water the natural rhythm, besides being quicker, is not so regular as it is in cold water: thus also it is with the artificial rhythm. Lastly, water below 20° or above 85° suspends the natural rhythm; and the artificial rhythm is suspended at about the same degrees. (e) Carbonic acid retards and eventually suspends the artificial rhythm, in just the same way as this gas acts on the natural rhythm. (d) When the marginal ganglia of Sarsia are removed, the manubrium shortly afterwards relaxes to five or six times its normal length. There can be no doubt that this effect is due to the muscular fibres of the manubrium having been previously kept in a state of tonic contraction by means of a continuous ganglionic discharge from the margin. Now physiologists are unanimous in regarding muscular tonus as a kind of gentle tetanus due to a persistent ganglionic stimulation; and against this opinion nothing can be said. But, in accordance with the accepted theory of ganglionic action, physiologists further suppose that the only reason why some muscles are thrown into a state of tonus by ganglionic stimulation, while other muscles are thrown into a state of rhythmic action by the same means, is because the resistance to the passage of the stimulation from the ganglion to the muscle is less in the former than in the latter case. On the other hand, the new theory of ganglionic action explains the difference by supposing a different degree of irritability on the part of the muscles in the two cases; for it will be remembered that in the author's experiments on paralyzed Aurelia, if the continuous stimulation were of somewhat more than minimal intensity, tetanus was the result, while if such stimulation were but of minimal intensity, the result was rhythmic action. Now the author finds in the case of Sarsia that the muscular tissue of the manubrium is more excitable than the muscular tissue of the bell; so that, for this and other reasons, the facts here accord more closely with the exhaustion than with the resistance theory of ganglionic action. Reflex Action.-The occurrence of reflex action in the Medusa is of a very marked character. For instance, if the manubrium be irritated, the swimming-organ responds to the irritation by giving one or more contractions; but if the marginal ganglia be now removed, the swimming-organ no longer responds even to the most violent irritation. Again, in Aurelia, if only one lithocyst be left in situ, and if, during a pause in the activity of the latter, any part of the irritable surface of the Thus far the results are strikingly similar to those obtained by Dr. Forster in the case of the heart-apex. swimming-organ be very gently irritated, the resulting contractile wave does not start from the immediate seat of irritation, but from the ganglion which still remains in situ. But this allusion to a "contractile wave " renders it necessary to state that all the contractile motions of the Medusa (whether due to ganglionic or to artificial stimulation) may be seen to be of the nature of contractile waves which spread from the point of stimulation as from a centre. The rate at which they travel varies greatly in different species, and in the same species under different conditions of temperature, &c. The author has made an elaborate series of experiments by section, with the view of ascertaining whether these contractile waves are merely muscle-waves or depend for their passage upon the presence of rudimentary nerves. He finds that the tissue will endure almost any severity of overlapping sections without suffering loss of its physiological continuity-the contractile waves still continuing to zigzag back and fore among the overlapping cuts. Similarly with another form of section, which consists in carrying a cut round and round the swimming-disk in the form of a spiral, the Medusa being thus converted into the form of a ribbon. In such a form of section the author has repeatedly seen contractile waves passing freely from end to end of a ribbon-shaped strip of tissue measuring only an inch across and more than a yard in length. He was therefore at first inclined to regard these contractile waves as merely muscle-waves. Nevertheless there is likewise an important body of evidence to be adduced in favour of a nervous plexus. In particular, if the spiral mode of section be carried on suthciently far, a point is, sooner or later, sure to come at which the contractile waves cease to pass forward: they become blocked at that point, and this always with great suddenness. Moreover, the point at which such blocking of the waves takes place is extremely variable in different individuals of the same species. Lastly, the fact that reflex action has been proved to occur, shows that these excitable tissues are pervaded by tracts which present the distinguishing function of nerve, viz. the conveying of impressions to a distance. And it is of the first importance to observe that this function is quite as difficult to destroy by the introduction of overlapping or of spiral cuts as is the function on which the passage of contractile waves depends. In other words, reflex action continues to take place through forms of section as severe as those through which contractile waves continue to pass. And this fact the author considers the most important that has as yet been brought to light in the whole range of invertebrate physiology; for he regards it as evidence that in these primitive nervo-muscular tissues the conductile or nervous element becomes differentiated from the contractile or muscular element in such a way that vicarious action is permitted to take place to any extent among the incipient conductile elements. And in striking confirmation of this view another series of observations may here be mentioned. Tiaropsis indicans is a bowl-shaped species of naked-eyed Medusa, to which the author has assigned this name in reference to a highly interesting function that is manifested by its manubrium. This function consists in the organ localizing, with the utmost precision, any point of irritation which is situated in the bell. For instance, if any point in the irritable surface of the bell be pricked with a needle, the manubrium moves over towards that point and applies its tapered extremity to the exact spot where the prick has been inflicted. But now, this unerring precision with which the manubrium indicates a seat of irritation in the bell may be completely destroyed by introducing a short cut between the base of the manubrium and the seat of irritation in the bell. The afferent connexions, therefore, on which this localizing function depends are thus shown to be exclusively, or almost exclusively, radial. But although under these conditions the manubrium is no longer able to localize the seat of irritation, it nevertheless continues to perceive, so to speak, that irritation is being applied somewhere; for every time the irritation is applied the manubrium actively dodges about from one part of the bell to another, applying its extremity now at this place and now at that one, as if seeking in vain for the offending body. Now this fact shows that the stimulus, on reaching the point at which the afferent tract is severed, escapes from the severed to the unsevered tracts through the vicarious action of the latter. There is another point of interest connected with this apparently reflex action. When the author removed the manubrium at its base, he found that on now irritating any part of its own substance the apex endeavoured to curve down towards the seat of irritation. Similarly, if only a portion of the manubrium were removed, the pointing action of that portion resembled the pointing action of the entire organ, while the stump that remained in situ would continue to move over as far as it could towards any point of irritation situated in the bell. Hence there can be no doubt that every part of the manubrium is independently endowed with the capacity of localizing a seat of irritation either in its own substance or in that of the bell. And in this we have a very remarkable fact; for the localizing function which is so very efficiently performed by the manubrium of this Medusa, and which, if any thing resembling it occurred in the higher animals, would certainly have definite ganglionic centres for its structural correlative, is here shared equally by every part of the exceedingly tenuous contractile tissue that forms the outer surface of the organ. We have thus in this case a general diffusion of ganglionic function, which is coextensive with the contractile tissues of the organ. Poisons. The author has conducted a number of experiments with reference to the effects of the various nerve- and muscle-poisons on the primitive nervo-muscular tissues. He has tried chloroform, ether, morphia, caffein, nitrate of amyl, alcohol, nicotin, strychnia, veratrium, digitalin, atropia, curare, cyanide of potassium, &c., &c., and he finds that in the main all these poisons exert precisely the same effects on the Medusæ as they do on the higher animals. A vast number of other observations were detailed which do not admit of being briefly abstracted. Those who are interested in the subject are therefore referred to the Philosophical Transactions,' where a full account of the research is to be found. New Researches on the Electrical Phenomena consequent on Irritation of the Leaves of the Fly-trap (Dionæa muscipula). By Prof. BURDON SANDERSON, F.R.S. On the Nervous Apparatus of the Lungs. By Dr. WILLIAM STIRLING. An Account of Finger-muscles found in the Greenland Right Whale. An Account of Dissections of the supposed Rudimentary Hind Limb of the Greenland Right Whale. By Prof. STRUTHERS. On the Structure of the Placenta in relation to the Theory of Evolution. By Prof. W. TURNER, F.R.S.E. On the Effects of the Mineral Substances in Drinking-Water on the Health of the Community. By J. A. WANKLYN. ANTHROPOLOGY. [For A. Russel Wallace's Address, see page 100.] On the Oldest Woman in Scotland. By General Sir J. ALEXANDER. On some Phenomena associated with Abnormal Conditions of Mind. Primitive Agriculture. By A. W. BUCKLAND, M.A.I. Believing the study of Primitive Agriculture to be of great importance in connexion with the migrations and social intercourse of races in the prehistoric times, I have endeavoured to show : 1st. The antiquity of the art and its bearing upon civilization; that it could only have originated among people having a settled abode, and therefore was probably first practised in a very imperfect state by the women of tribes left in tents or villages to await the return of hunters-a probability which is strengthened by the fact that women are still the sole agriculturists among many semicivilized races. 2nd. That although agriculture may have originated in many lands and at different times, many peoples yet remain in total ignorance of it, and the agriculture of the lower races consists in the cultivation of indigenous roots and fruits, the cultivation of the cereals being confined to civilized races and to those who have learnt it through contact with them. 3rd. That the origin and native land of all the cereals remains obscure, although all, excepting maize, are supposed to be indigenous in the eastern hemisphere, whilst maize is affirmed to be of American origin and to have been unknown in the Old World before the time of Columbus. This last assertion I have ventured to dispute, from the fact that travellers have found it in cultivation in various parts of Asia and Africa before any intercourse had arisen with white men, and because it is described in the 'Niewe Herball' published 1578, as Frumentum Turcicum or Asiaticum. 4th. That there are traces in America, China, and ancient Egypt of a time, anterior to the cultivation of cereals, when the aborigines of these countries fed, as the Pacific-islanders do now, upon fruits and roots, some of them poisonous, but rendered wholesome by pounding, maceration, and desiccation, and that this primitive state in these countries is confirmed by the annals of China, by the testimony of Herodotus, and by American myths. 5th. That a similarity in the customs, myths, monuments, and religions of China, Egypt, Peru, and Mexico leads to the conclusion that a cognate pre-Aryan race introduced the cultivation of the cereals into all these countries, and with them the worship of the Moon as an agricultural deity. 6th. That the absence of agricultural implements from prehistoric discoveries proves their extreme simplicity, being probably only a pointed stick, which still forms the sole agricultural implement in many countries, whilst it is not improbable that some of the stone celts were employed as hoes, and that flint flakes inserted in wooden frames served then, as they do now in the East, as harrows and threshing implements; and that furrows and ridges seem everywhere to have been used in the cultivation of grain, whilst corn-hills seem to be confined to America, although used in Africa in the cultivation of mandioca. 7th. That the traces of primitive agriculture confirm the conclusions of modern ethnologists as to the early condition, gradual development, and extensive migrations of the human race. On Relation of Gaelic and English. By Rev. Mr. CAMERON, On the Prehistoric Names for Man, Monkey, Lizard, §c. By HYDE CLARKE, M.A.I. The writer first stated that the Australians call the white man Wanda, also a word for spirit, demon, or angel. In African languages, Wanduni and Wani are names for man: the names for man in African and Central-American languages interchanged with those for monkey, lizard, frog; of these numerous examples were given. In Assyrian monkey is "udumu," which Rev. W. Houghton compares with the Hebrew Adam as related to the anthropoid ape. The Aryan Man and Son are found in Africa and the prehistoric world in such relation as all Aryan pre-historic roots are. There was no separate creation or development of Aryan roots, though there was a selection, and Sanskrit words may be found among some of the lowest savages in Africa. This thing is certain, that the Aryan languages were first those of blacks, as are most of the languages of the world, and the words supposed to represent an Aryan civilization are those of the culture of the earliest blacks and savages. So, too, as to primitive mythology, in the facts above stated will perhaps be found the origin of telem worship and of animal ancestors. On Hittite, Khita, Hamath, Canaanite, Lydian, Etruscan, Peruvian, This paper embraces the author's investigations on that family and epoch to which he had given the name of Sumero-Peruvian, but to which the title of Hittite had lately been given. Beginning with the Canaanites, the Hittites, &c., he stated his investigations as to the decipherment of the Hittite or Hamath inscriptions and the Canaanite terms in the Bible. This part embraced in copious tables the parallelism of Canaanite town names recorded in Scripture with those of Asia Minor, pre-Hellenic Greece, Etruria, Italy, Iberian Spain (not Basque), Babylonia, India, Peru, and Mexico. Applying this evidence again to support the linguistic, the community of Etruscan with Lydian and Hittite was affirmed. The earliest culture of India was assigned to the same family. Adopting the mass of evidence, the languages and culture of the great kingdoms of America were explained as being of a like epoch with the "Hittite," and the phenomena of an arrested culture in America were accounted for. Thus while there were points of conformity in culture and mythology, America never shared in the highest stages in the Semitic or Aryan developments. Traces of the tradition of the former communication with the New World were illustrated. On a Sooloo Skull. By Prof. CLELAND, F.R.S. On the Phoenicians. By C. O. GROOM NAPIER. On the Natives of British Guiana. By W. HARPER. On the Eastern Picture-writing. By J. PARK HARRISON. On the Rodiyas of Ceylon. By BERTRAM F. HARTSHORNE. On Horned Men of Akkem, in Africa. |