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interruption. The Aciclovir Buy columns of Burdach and Goll, for ex- ample, terminate in the nuclei of those columns, the direct myelo-cerebellar tract runs into the cerebellum, and other less individualized fibre-systems, which may possibly have a relation to sensory functions, are connected with and provisionally at least terminate in some. one or other ganglionic way-station or terminus. If on comparing the relative development in Aciclovir 5 Cream various animals of the intcrnodial ganglia connected with these tracts, it were found that they are less developed in higher than in lower animals, it might be inferred, as I urged with regard to certain other ganglia and tracts, that they represented necessary steps in phyllogenetic development, destined like the human tail, and the notochordal relic in the ligamentum suspensorium dentis epistrophei, to be- come obsolete. For nerve-tracts subservient to higher functions do exhibit a tendency to Aciclovir Dispersible Tablets emancipate themselves from ganglionic interruptions, probably because a direct tolegraiihic connection — cceteris paribus — is a more per- fect mechanism than one which has to pass many inter- rupting stations. But this is not the case with regard to the ganglia under consideration. Their interrupting stations, such as the nuclei of the columns of Goll and Burdach, and the dentated Aciclovir Bp nucleus of the olive, attain their highest develop- ment in man and the anthropoid apes. There is as much of higher individuality in the varying contours of the last- named body, as there is in the cerebral hemisjiheres them- selves ; just as the monkeys alone resemble man in the type of cerebral convolution, so they alone of all animals present anything like the same character, relations, and degree of olivary corrugation.' If there is any inference to be drawn as to the physiological importance from rela- ' And this not as an expression of generally high cerebral development in the anthropomoniha;, but of affinity in zoological position, and, what is practically equivalent, of peripheral disposition, for theclcpiiant and porpoise, with far moie complexly convoluted hemispheres than man even, have simpler olivary bodies, resembling those of their humbler congeners the hog and the sea-lion. Meynert it utterly at sea where he refers to the remarkable development of the olive m marine mammals, for the same elevation passes as the pyramids in Hiigucnin's treatise. 394 THE MEDICAL RECORD. [October ii, i! live development, these interrupting stations must be regarded as important factors in the central laboratory. Tliis is almost the same tale as that which might be told of the cerebellum ; a ganglion, which may be regarded as a gigantic way-station, in which auditory and spinal tracts meet, and are continued brainward, through cerebello- cerebral fasciculi. It was not so very Buy Aciclovir Tablets Uk long ago supposed that the cerebellum as a " lower centre '' was crowded out by the higher cerebrum in the ascending animal series, whereas the fact is that this ganglion is vastly larger and more intricate in higher animals than in lower ones, and shows an individuality in the type of its foliated arrange- ment, comparable to that adverted to in the case of the olivary nuclei. It being thus evident on structural grounds that the gan- glionic enlargements in which certain spinal tracts appear to terminate have an object, which could not be Aciclovir Cream Bp fulfilled if those tracts ran directly to the cortex, we must look to the other connections of sucii ganglionic masses for an explanation Aciclovir Eye Ointment of that object. To take a hypothetical case. Suppose the cerebellum received fibres from the skin through the " sensory tracts " in the cord, and from the semicircular canals through the auditory nerve, and de- spatched another tract to the cerebrum ; assuming that the direction of functional transmission were in all these tracts toward the cerebrum, there could be but Buy Aciclovir Tablets one conclusion : that the cerebellum served to co-ordinate and fuse space sense perceptions from the skin, and such from the semicircular canals, and acted as an informing depot for the cerebrum ; the latter is through its inform- ant, which spares the cerebrum the task of co-ordinating these impressions into a united general space sense, enabled to guide motion in accordance with the latter.' The probable object of the internodial or interrupting ganglia is the mediation of some functional combination. The manifold interruption of the tracts of sensation, as contrasted with the direct course of the tract of voluntary motion, hence appears as the anatomical expression of the fact that the motor impulse is a comparatively simple step, but that the building up of the contact and space senses which guide such motion to a skilful purpose is a far more intricate and laborious task, which is thrown on the centripetal tracts, and hence requires a greater ana- tomical complication. I need but cite briefly a few facts recently observed by me in an interesting case' which justify the surmise above expressed, that certain tracts physiologically and ana- tomically regarded Aciclovir Tablets Buy Online as centripetal really may convey func- tions centrifugally in a part of their course. An elderly gentleman, after a small hemorrhage in the pons, which caused unilateral ataxia of the opposite extremities, lived six years, during which time an intense secondarv degen- eration developed in the descending direction, and termi- nated after decussating in the opposite nuclei of the col- umns of (JoU and Burdach, which were likewise atrophic. Now as far as secondary degenerations follow any law,' It is supposed that if a ganglion degenerates together with an appended tract, that both must belong to the same physiological system. The columns of Goll and the upper part of the columns of Burdach degenerate centrip- etally, that is, upward, or toward their nuclei. The dis- eased tract in my patient had degenerated centrifugally, that is, cordward, and hence from an opiiosite direction, also to7t>ard these nuclei. Here is an unquestionable in- stance in which two segments of the same tract — for the upper segment must be regarded as in part the cephalic continuation of the lower — degenerate toward an inter ' The facts happen to justify this hypothesis, to some extent. As bearing on what the writer said about the possibility of tracts customarily regarded as centrip- etal convepng centrifugal funclions, it Aciclovir Cold Sore Cream may be well to refer to the fact that if Hechsig Where To Buy Aciclovir s suspicion, that the direct niyelo-cerebellar tract is centrifugal turn out to be well founded, that the cerebellum may exert a direct influence on a cer- Buy Aciclovir tain class of movements, without the inter\'ention of the cerebrum at all This would but increase the force of the remarks made in the text, as to the importance ofthe" interrupting" and "co-ordinating" stations. The above idea has been borrowed, with others, by Ranney. ^ This case has been reported elsewhere, to be hereinafter referred to when the questions involved will be more fully discussed. ' I Aciclovir Tablets To Buy justifying the assumption that functional impressions converge toward it, though not excluding the possibility of a continuous transmission brainward of sensory impressions ' at the same time. I have considered it necessary to make these introduc- tory remarks, because to me the impression seems to pre- vail that all that is necessary to understand the anatomical part of the cerebral mechanism is the tracing of the cen- tripetal tracts to the muscles in which they terminate, and the centrifugal ones to the cortical fields, from the periph- eries, whose impressions they convey to them. This is important and essential, but it does not Aciclovir 800mg exhaust the duties of the anatomical psychologist, and is not even feasible in the case of many fasciculi. \\'hat I said some years ago " with regard to the functions of nerve-centres generally, " That day is past when it could be considered legitimate to refer every phenomenon provoked by an intracranial experiment to an altered activity of any single centre ! " naturally ajiplies also to the nerve-tracts whose connection with the nerve-centres is a factor in the func- tion of the latter. With these preliminary remarks, I have intended to pave the way for the understanding of the lemniscus : a nerve-tract of at least equal importance with that of the pyramids, an importance which is just being recognized, and which from its manifold, systemic, and topographical relations ofters an opportunity for the discussion of many new or imperfectly understood features of isthmus anatomy. II. Buy Aciclovir Online — External and Gross Anatomy of the Lemnis- cus. On the outer (lateral) face of the mesencephalon, that is, on the slope which intervenes between the corpora quadrigemina and the bulging pes of the cerebral pedun- cle of each side, there is a distinctly marked triangular field, known as the lemniscus or laqueus.. This is not merely a surface feature of the brain- isthmus (or axis), but the exposure of a great brain- tract, which in this particular area is uncovered by other nerve tissues, and elsewhere is deeply imbedded in the substance of the thalamus region, Aciclovir Cold Sore \\\^ pons, Valaciclovir Vs Aciclovir and passing through the oblongata, becomes intimately related with the ganglionic elements of the great centripetal columns of the cord, namely, the nuclei of the columns of Goll and Burdach, as well as the dentated body of the olive. Just as the columnar elevations of the oblongata, known as the pyramids, represent only a small segment of that great system, the will-tract, to which they have given the anatomical name of " pyramid-tract," so the surface area of the lemniscus indicates but an insignificant por- tion of the great tract which bears the same designation. Haller ° discovered the lemniscus, describing its situa- tion and shape, but to Reil * is owing the credit of having recognized that the triangular field discovered by Haller is only the surface denudation of an important system of fibres. He found that it was not in connection with the pyramids, though some admixture of the fibres of the fillet and the pyramid was alleged by him, and traced it to the situation to-day known as the stratum of the fillet (Schleifenschicht). He later claimed that it passed be- tween the olivary nuclei and the pyramids in the ob- longata, and Aciclovir Tablets 800mg became indistinguishably fused with both of these bodies. Rosenthal undertook to correct this latter statement, which, as far as the pyramids are concerned, is partly true, for my own case demonstrated the existence of ^ Or of hitherto unsuspected centrifugal transmission cordward. The column;: Goll may occasionally degenerate downward or simultaneously with their nuclei : least this Aciclovir Tablets 200mg seems to have been so in Sioli's case (Archivf. Psychiatric, xi., 3, p. 693). This surmise would offer the explanation of possible physiological transition for the case of some rodents, like the rat, in whom, according to Flechsig, the fibres of the true (?) pyramidal decussation enter the posterior columns. 2 The Architecture of the Oblongata, N. Y. Medical Journal, September, 1881. It is refreshing to find this identical conception emanating from another writer in the same journal several years after. Unfortunately the context of his conclusion furnishes no hint as to the method by which he arrived at an opinion so similar in its phraseology' to the writer's. It is in fact a disconnected plagiarized sentence, like another previously referred to as appropriated from the same source. 3 Elementa I\'., p. 175. According to Burdach.; -_ * Reil's Archiv, ix., p. 149. October ii, 1884.] THE MEDICAL RECORD. 395 of degenerated fasciculi in the otherwise healthy pyramid, and these were connected with the degenerated inter- olivary field. The discover)- of Hallei was ignored by the anatomists who described the mesencephalon after his time, and before that of Reil. Vicq d'Azyr," whose plates are usually singularly true to nature, represents the lateral field of the mesencephalon as a uniform rounded surface, and neither designates nor describes ilie lemniscus, while

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