to Man, approaches that of the young Child, I need not stop to point out. But further, an examination of the Anatomical relation of the Cerebrum to the Sensorium, taken in connection with the fact ascertained by experiment that no injury to the substance of the Cerebrum itself calls forth pain, seems to justify the Physiological inference, that we only become conscious of Ideational changes of which the Cerebrum is the instrument, through the transmission of the "impressions" of those changes to the Sensory tract at its base. This doctrine has so extensive a Psychological bearing, that I may be excused for entering into a somewhat detailed explanation of it. Every Anatomist knows that the arrangement of the Nervous elements in the Cerebrum is so far exceptional, that the "grey matter" which constitutes its active portion is disposed on its surface, forming the "cortical layer;" the disposition of which in "convolutions" allows it to come into that direct relation with a vast expanse of capillary Blood-vessels, which is necessary for its functional activity. On the other hand, the "medullary" interior of the Brain-substance has exactly the same fibrous structure as the Nerve-trunks; and though this was very imperfectly known before the microscope came into use, the resemblance was sufficient to cause that very sagacious old Anatomist, Reil, to name the radiating Common as such occurrences are, they fibres which connect the cortical sub- have scarcely, I think, received the attenstance of the Cerebrum with the Sensory tion they deserve. They seem, in the Tract, the "Nerves of the internal first place, to indicate that "remembered senses." Now if, as Comparative Anato- Sensations " are not direct reproducmy seems distinctly to teach, this Sen- tions of former Sensorial states, but are sory tract is the instrument whereby we brought back by Ideational Associations; are rendered conscious of external im- that is to say, that they are called up by pressions, and the transmission of the internal Ideas, just as they were origi"nervous modifications," thus excited in nally excited by external Impressions, the Sensorium, to the cortical substance or, in other words, that we should have of the Cerebrum, through the ascending no memory for Sensations, were it not for fibres, furnishes the instrumentality their association with Ideas. Further, if whereby Sensations call up Ideas,- there seems equal reason for believing that when Ideational changes in the Cerebrum give rise to Sensations, they do so by transmitting back to the Sensory Tract, through the descending fibres, some "nervous modification " which those changes involve; thus producing in the Sensorium the same physical condition, whatever may be its nature, as that through which the Sensation was originally excited. loathsome decomposition, the stench of which induced vomiting, this feeling strongly returned upon him some years afterwards, when, on passing the same place, the remembrance of what he had previously seen recurred vividly to his mind. There can, as it seems to me, be no reasonable doubt that the Ideational (Cerebral) state called up by the local Association, excited the same change in his Sensorium, that the Visual impression of the disgusting object had done in the first instance; for how else can we account for the fact, that the same impulse to vomit immediately supervened? The experience of most persons, embodied in the familiar phrase, "It makes me sick to think of it," bears further testimony to the same conclusion. I myself know persons so sensitive to the impressions which produce sea-sickness, that they begin to experience it on going on board a vessel for a sea-passage, even before she has quitted her moorings; and I have been assured on good authority, that the mere sight of an agitated sea on which a friend was about to embark, proved sufficient to bring on a paroxysm of sea-sickness in the person of one lady; whilst another was affected in the same manner by watching a model, in which, by an ingenious mechanical arrangement, the motion of a ship at sea was extremely well imitated. Thus Van Swieten records of himself, that having once passed a place where the body of a dog was lying in a state of the Sensorium really consists in the aggregate of the Ganglionic centres of the Sensory nerves, whilst the Cerebrum is the instrument of all Ideational operations, we must either suppose that the Sensorium for remembered sensations is different from the Sensorium for primary Sensations, or we must recognize the unity of the Sensorium in its common relation to the nerves of the external and to those of the internal senses, whereby a Sensorial state identically the same may be called up by an impression conveyed by either one or the other. More than twenty years ago, Mr. John Mill wrote to me that he considered this representation of an object, different doctrine of the singleness of the Sen- from that through which we become Sensorial centre, so that we become con- sationally conscious of its properties. scious of states of Perception and Conception through the same instrumentality, to be one of the most important contributions that Physiology had paid to Psychology. The acceptance of this doctrine, again, furnishes a Physiological rationale for the fact, which Metaphysicians of all Schools admit, whatever may be their way of accounting for it-that when a "chain of Associations" has once been formed, the two terminal Ideas may come into communication, without the conscious intermediation of those which originally linked them together; so that, the original chain having been composed of A, B, C, D, If this be true of remembered Sensations, it can scarcely be otherwise of remembered Ideas; their record being Cerebral, whilst the awakening of the consciousness to that record is Sensorial. And we thus gain some insight into the mechanism of one of the most remarkable facts in Psy--A may directly excite D, without B and chology, that the record of past Ideas, which constitutes our knowledge, may lie beyond the range of recall for any length of time, and may yet be made to impress the consciousness (so that those past Ideas come to be remembered with the most intense vividness) by some change in the condition of the Brain which seems to be of a purely physical nature. For if the doctrine here advocated be correct, the Anatomical and Physiological relations of the Sensorium to the cortical substance of the Cerebrum, and to the Retina, are exactly the same; so that, as no modification produced in the Retina can affect our Consciousness, save by the transmission of a change along the Optic Nerve which excites a certain Physical action in the Sensorium, so no Ideational modification of the Cerebrum can affect our Consciousness, save by the transmission of a change along the nerves of the Internal senses, which excites an analogous Physical action in the Sensorium. C coming into the mind at all. Sir William Hamilton and Mr. John Mill, for example, agree in recognizing this as one of the commonest operations of our Minds; and while the former, in common with the Psychologists of Germany, describes it as an example of "Latent Thought' the latter regards it as indicating the occurrence of cerebral changes, which do not themselves come within the "sphere of consciousness," but which excite other changes that do,- a conclusion being reached in this manner, without our being at all aware of any processes of Thought by which it has been arrived at. And although there are Metaphysicians who still assert that there can be no such operation, and that, in every case in which it is supposed to take place, there has been a train of conscious, though not remembered thought, it may be simply replied that they can furnish no proof of their assertion, and that it runs counter to the common consciousness of Mankind. I myself arrived at the view here advocated, What this "physical action" is, and on Anatomical and Physiological considhow it awakens our Consciousness, we erations alone; and it was not until I indo not know. and perhaps never may terrogated my own consciousness as to know; but since it is a fundamental fact "whether these things were so," that I of our nature as regards Sensations, which came to recognize this form of Cerebral the purest Metaphysician must recognize, action in the familiar phenomenon of the I see no reason why we should refuse to spontaneous "flashing" into the mind of accept it in the case of Ideas. The trans- something which one has been vainly trylation (so to speak) of any kind of physi- ing to recall, the attention having been cal modification into any form of Con- transferred in the mean time to something sciousness, Sensorial, Emotional, or entirely different. And the fact that this Ideational, is the great difficulty; but I conclusion harmonized completely with do not see why the difficulty is greater in what had been taught for two centuries the case of one form of Consciousness, in Germany as a fundamental fact in Psythan in that of another. And by regard-chology, without any reference whatever ing the immediate antecedent as the same (so far as I am aware) to Physiological in all cases, and in assigning to the considerations, gives it, I venture to think, same Sensorial centre the consciousness a primâ facie claim to acceptance as a sciof Sensations and the consciousness of entific rationale of the phenomena in Ideas, we get rid of the great difficulty of question. making the instrumentality through which The able and friendly critic in the we become conscious of an Ideational | Spectator, who has more than once noticed time, any Memory whatever; and as the affirmation that there are such states is obviously incapable of proof, it cannot be accepted as a justification of the refusal to admit that changes which ultimately give rise to Ideational states may take place outside the "sphere of consciousness." 66 my Psychological contributions to this Review, objects to the doctrine of "Unconscious Cerebration" as "in the highest degree improbable." If it be admitted, he says, "then thought itself might be regarded as due to purely physiological machinery; in which case, there would be no wonder in the mind's passing without consciousness through a compliI would further adduce in support of cated chain, not of course of thoughts, but my position the well-considered judgment of the nervous changes which correspond which Mr. John Mill has delivered on this to thoughts, and returning again to con- point, in his examination of Sir Willlam sciousness at any link in the chain. But, Hamilton's Philosophy and his notes on as far as we can see, the physiological James Mill's Analysis. Dissenting entirely enquiries of recent days do not in the from Sir William Hamilton's mode of exleast degree tend to show that you can pressing the facts, Mr. Mill says:-" That pass through a line of closely-associated a feeling should not be felt, appears to thoughts without conscious thinking, as me a contradiction both in words and in you can undeniably pass through a line nature." But," he continues, "though of closely-associated habitual actions with- a feeling cannot exist without being felt, out thinking." Now, at the risk of being the organic state which is the antecedent stigmatized as a "materialist," I must of it may exist, and the feeling itself not honestly avow my conviction that Thought, follow. This happens, either if the or-in so far as it is Automatic, and not ganic state is not of sufficient duration, Volitional, — has just the same relation or if an organic state stronger than itself, to "physiological machinery" that Sensa- conflicting with it, is affecting us at the tion has; and that there is just the same same moment. Hence if we admit (what reason for asserting that mental Feelings | Physiology is rendering more and more depend (in the scientific sense) upon probable) that our mental feelings, as well "physical antecedents," as there is for as our sensations, have for their physical attributing bodily Feelings to "physical antecedents particular states of our nerves, antecedents." And unless the Spectator it may well be believed that the apparis prepared to affirm that he can see by ently suppressed links in a chain of Assohis Mind alone, without the instrumental-ciation, those which Sir William Hamility of Eyes, Optic nerves, and Sensorium, ton considers as latent, really are so; -in which case, of course, the Physiolo- that they are not even momentarily felt; gist has no common ground with him, the chain of causation being continued I would submit to his consideration, that only physically, by one organic state of the fact that links in the chain of Associa- the nerves succeeding another so rapidly, tion do drop out of the consciousness is that the state of mental consciousness not an invention of Physiologists, nor a appropriate to each is not produced." mere assertion of Metaphysicians, but the daily experience of every one who analyzes his own mental processes. The analogy of unremembered states of consciousness in Sleep, Somnambulism, &c., -cited in the Spectator in support of the explanation that these dropped ideas have actually passed before our consciousness, but are simply not recollected, is not a just one; since these are all states of "second consciousness," in which, when it is most characteristically developed, the Memory is perfect between one of these abnormal states and the next recurrence of it, although nothing whatever of what has passed in the abnormal state may be remembered in the ordinary waking state. The question is, whether states of Consciousness can exist in the ordinary waking condition, of which there is neither immediately, nor at any subsequent | Memory. It is obvious that Mr. Mill takes quite a different view from the Spectator as to the tendency of "Modern Physiology; and as I know that he has constantly kept himself au courant with its progress, I attach the more weight to his recent deliverance on the subject. Quite agreeing with the Spectator, however, that a right appreciation of what the Physical Mechanism of Thought can, and of what it cannot do, is of fundamental importance in the inquiry as to the Hereditary Transmission of capacity for particular forms of thought, I shall, in the next portion of this paper, take as an illustrative example of the causal relation between Physical changes in the Nervous System, and definite modes of Mental action, that aggregate of Mental phenomena, which we group under the general term W. B. CARPENTER. From Nature. appearance of rippled water where they A PETRIFIED FOREST IN THE LIBYAN reflect the sunlight. The zoology and DESERT. On the western horizon of the Libyan Desert, as viewed from the summit of the Great Pyramid of Ghizeh, a conical hill stands in solitary grandeur, far removed a caravan. botany, too, of the desert are very interesting. There are numbers of the little "jerboa," a species of rat, with long hind legs and long tail with a tuft of hair at its Now and then may be seen a gazelle or end, which hops about like a kangaroo. from the route of desert travellers. This has long been supposed to be the ruins two scampering off at the unusual sight of of a pyramid, yet nowhere is it recorded carious existence, and in the sky an eagle A few small birds get a preto have been visited by any but the Bedouin tribes who pass within a few miles or vulture sometimes wings its way. The of it, on the old caravan route to the Fai-tremely scant, and it is a marvel what the insects are few, and the herbage is exoom. It is enumerated by Lepsius as one animals live on. of the Pyramids of Egypt, and in a recent there in the water-courses small tufts work on the Great Pyramid it is called of camel-thorn-a little shrub not unDr. Leider's Pyramid, "until a better name be found for it," merely from its like a whin, another with a coral-like having been pointed out to the author by growth, and now and then a handful of a the late Dr. Leider of Cairo, who, how-tough wiry sort of grass, but what these ever, had never visited it. The following narrative of a visit to the eminence by Mr. Waynman Dixon, engineer, and Dr. Grant of Cairo, and of their discovery of a very remarkable petrified forest near its base, whose gigantic trees lie scattered about the desert in profusion, has been communicated to us by the former gentleman : Leaving the pyramids behind and lighted by the clear silvery moonlight, we set out into the desert by the caravan route to the Faioom, leading up a solitary valley, in the rocks of which are cut ancient Egyptian tanks and mummy-pits. Presently we turn off from the regular track and take our way into the unfrequented desert, steering straight westward for the distant pyramidal hill. The sand of the desert is here hard and compact, and travelling easy, indeed, with the exception of one or two places where the sand is soft and heavy, a wheeled carriage might drive all the way, and to most travellers would be much preferable to camel or even donkey riding. After many hours? hard riding, we at last reach the top of a slight eminence, and across the wide valley in front of us is the place of our destination. These long valleys, or "wadys," have much of interest about them; throughout may be seen the dry water-courses where the rare rain-showers carry down the sand into the bed, and leave all the little hills and eminences covered by flints as big as potatoes and with surfaces so brightly polished as to give the desert a silvery look by moonlight, or by day to cause the "Life and Work at the Great Pyramid," by Prof. Piazzi Smyth, F.R.S. There are here and again subsist on it is hard to say, for there is not a shower more than once or twice a year, and for nine months there is no dew, while the heat of the sand at midday in summer is over 100 degrees. the break, we dismount from our camels, and Near the top the rock crops out, and appears to be a species of friable sandstone fretted by the weather into curious shapes; but the actual summit is covered with flints and sand, and, what strikes one as being very strange, many fragments of petrified wood. Taking a general survey from this quoin of vantage, we choose the best spot to the north of the hill to pitch our camp, exposed to the slight north wind which blows incessantly here, and descending its steep sides, at the bottom are surprised to find near the chosen spot three large stone trees lying prostrate on the sand. The largest is 51 ft. in length and 3 ft. 6 in. in diameter at its widest end, and 2 ft. at its smallest; they are branching exogenous trees, apparently a species of pine, and the one before us has the fork of a large branch very complete. Wandering on up the wady to the north of the hill, named by us "Kôm el Khashob " the hill of wood we find the whole desert littered with fragments of petrified wood, from twigs the size of was held in solution in the water that surrounded it. one's finger to pieces of large branches or trunks of trees; and on the flank of the hill to the north are hundreds of immense Since the discovery of this forest it has trees, lying half buried in the sand, some been visited by many Europeans in Cairo, 70 feet long, and in many instances with and English travellers, and to geologists part of the bark still attached. All of especially it is well worthy of a visit. It them are exogenous trees no single in- may easily be reached from the Great stance of a palm could we discover and Pyramid either by donkey, camel, or from the absence of roots it may be pre- horse, and is distant under three hours sumed have been drifted here by the sea. from it- a journey which in the winter The stratum is apparently sandstone, may with comfort be accomplished in one overlying the limestone of the Nile val- day from Cairo. Indeed, if his Highness, ley; there are also here and there patches the Khedive, who has done so much for of a dark chocolate-coloured friable min- the comfort of travellers in making a mageral with specks of green which looked nificent road to the pyramids, were to exlike copper, but proved on subsequent tend it for some half mile farther through analysis to be carbonate of iron; beds of the tract of soft sand, carriages could what the Arabs call "Gyps" or gypsum, easily drive all the way to the Kôm el and nodules of an intensely hard black | Khashob. The locality is now well known granulated looking stone not unlike to the Pyramid Arabs, and most able and emery stone. The whole geological char- intelligent guides will be found in Ali acter suggesting the possibly delusive Dobree, Omar, or others of this Bedouin -suspicion of the existence of coal under tribe. the surface. Having carefully surveyed this neighbourhood we again climbed the "Kôm el Khashob," taking instruments to measure its height and determine its position; the former of which we found to be 752 ft. above the Nile level at Cairo, 602 ft. above the north-east socket of the Great Pyramid, and consequently about 140 ft. higher than its summit. From The Spectator. ST. CHRYSOSTOM.* Mr. STEPHENS has produced a work of permanent interest and value in this Life and Times of Saint Chrysostom. He is not, indeed, free from the fault which seems almost inseparable from the office of biographer, the incapacity of putting himself in the position of those who disliked and opposed his hero. Whatever we may think of the virtues and the genius of Chrysostom, it is impossible but that the prelates who brought about his downfall should have had some way of justifying their conduct to the world and to themselves. Posterity has condemned them with unanimous voice, but it is incredible that the patriarch of a great see, backed by a majority of the bishops of at Having secured one or two sketches of the hill, and the sun being now near setting, we "fold up our tents like the Arabs and silently steal away." Mounting our camels again, and taking a slightly different route on our return, we pass some ancient solitary well-tombs away in the desert, but without mark or hieroglyphic inscription on them. All the way we notice fragments of petrified wood, and near to the pyramids extensive beds of oyster shells. This forest may almost be said to be a continuation-doubtless going much farther westward than we pene-least one province, should have had no trated of the well-known petrified forest in the Abbasieh Desert to the east of Cairo, which extends a long way in the direction of Suez, but is inferior both in extent and in the size and perfectness of the trees to that of the newly-discovered forest. The formation of the land here would lead to the supposition that it has been the ancient coast line, and that the trees drifted to where they are now found, and were then left in the briny waters of an evaporating sea or salt lake; and as the fibre of the wood decayed slowly away, the space of each cell has been filled up by the crystallizing silica which motives for their conduct but vulgar jealousy or unreasoning dislike. If Mr. Stephens could have contrived to give us their view of the question, he would have given us a chapter not less interesting than any that we find in this volume. Another defect is, that in analzying, as he does, with a very elaborate care, separate homilies and treatises, he sometimes burdens his pages with matter of but little interest, while he fails to give his readers the Church and the Empire in the Fourth Century. By Rev. W. R. W. Stephens, M.A. London: John Murray. 1872. St. Chrysostom, his Life and Times: a Sketch of |