It is highly satisfactory, in view of the heterogeneous mass of apparently contradictory testimony with which Dr. Brown-Séquard has identified his name of late, to hear from Dr. Ferrier (page 40): "It is not maintained, however, that in all cases of purely cortical paralysis anatomical lesions are demonstrable in these centres; but I am unable, after much investigation, to find any satisfactory evidence of a destructive lesion here, not associated with motor paralysis." The famous "crow-bar" case has sometimes been brought forward as a piece of adverse evidence of this kind, but it is probable that the convolutions referred to in reality escaped injury. For the analysis of the evidence showing the probable position in man of the special" motor centres," we must refer the reader to the original essay. If the conclusions based thereon are justified, as is now almost universally believed, we may have in man complete paralysis either involving one entire half of the body, or limited to some of the movements of one member, from disease or injury confined to the cortex cerebri in the motor region referred to, and analogous disturbances of the special senses, from similar lesions in the more posterior portions of the cortex. Indeed, the hemiplegias of cortical origin are hardly, when fully developed, to be distinguished from those due to lesions of the deeper-lying parts.

The existence of other diseases (meningitis, etc.), and the mode of onset of the attack may help to a diagnosis. Thus we read (page 98), “Hemiplegia, complete from the first and permanent, is not, however, the most common type of paralysis depending on lesion of the cortex or subjacent medullary fibres. More frequently, paralysis of cortical origin is . . . a succession of dissociated paralyses or monoplegiæ. In cortical affections we frequently find a hemiplegia, at first complete, resolving itself into a monoplegia, or a monoplegia becoming a hemiplegia by progressive advance of the disease to other centres. Monoplegia is very often associated with monospasm, or early rigidity of the paralyzed limb. . . . Cortical paral ysis is frequently erratic and transitory, more especially in connection with superficial or meningo-encephalitis, appearing and then vanishing, first on one side and then on the other." "According as the lesion is superficial, or invading the whole depth of the cortex and subjacent medulla, we get transitory paralysis, or a paralysis which remains permanent and is followed by descending sclerosis and late rigidity," etc.

...

Additional evidence is brought to show that epilepsy (a name which, as Hughlings Jackson long ago pointed out, should be taken to indicate a pathological condition in which ganglionic matter anywhere may be found, and not the lesion of a certain organ, as the medulla oblongata) is often due to irritative lesions in the motor area of the cortex.

No extended attempt is made to analyze the functions of the so-called " centres" from the psychological stand-point, though what is said seems to us sound and interesting. We object, however, to the view, which is sanctioned not directly, but by implication, as to the significance of the movements induced by electrical excitation of the brain.

It is claimed that by this mode of experimentation we can study the localization of functions in the cortex cerebri, but it is plain that unless it is assumed that these movements are such as are characteristic of the conscious,

volitional life of the animal, they can give us only a very limited information as to what are generally believed to be the most important of the cortical func

tions.

It will be rejoined that the information given by the electrical experiments is both supplemented and corroborated by the testimony of the results (localized paralyses) of destructive lesions of the cortex. But even if this were entirely true (and it must be confessed that the testimony borne by the clinical observation is not always as explicit and satisfactory as could be wished), still we maintain that by thus allowing one of the functions of a very sizable portion of the cortex (the power to initiate simple fundamental movements) to stand as its representative function, an important source of error is introduced into the discussion.

Have, then, these movements any peculiarity which stamps them as of volitional type? It is easy to reason that, since all thought is made up of motor and sensitive elements, and since it must be in the cortex cerebri as the supreme ganglionic centre that these component elements of thought are constructed, therefore all manifestations of activity which we get from acting on the cortex in the physiological laboratory must be such as, occurring in the life of the individual, were characteristic of his conscious existence. This reasoning is not distinctly gone through, we repeat, only implied, and it is indeed now generally believed that the cortex cerebri has to do with secretion, nutrition, vaso-motor action, and perhaps all the processes of vegetative life. Still, the implication, even, that the simple muscular movements which we get by applying electricity to the cortex cerebri are of a volitional type deserves, in the interests of psychology, to be met and questioned.

If such were the case, how should we explain the fact that it is found to be impossible, experimentally, to excite any play of motions such as might suggest, in the faintest degree, by their variety or number, the voluntary movements. of a healthy animal? The first inclination is to suppose that this small and invariable circle of movements represents the average, so to speak, of the infinite number which each centre may take part in producing, in the sense in which Dr. Hughlings Jackson speaks of the tonic spasms of epilepsy as being made up of a great number of coördinated movements of high order "jammed together" so as to be individually indistinguishable. It is plain, however, that this analogy cannot be applied exactly to the case of experimental excitations of the cortex, since we see here no evidence of a conflict of muscular contractions, but orderly, unembarrassed, though not very complex motions, which recur always under essentially the same form. It may be that the reason we always get these particular movements, instead of any one of a large number, is that, in virtue of the frequency with which, physiologically, they occur, the processes underlying them come to have a greater susceptibility to excitations than the processes underlying other movements less frequently performed. But it must be remembered that this very fact would constitute a reason for classifying these processes among the (relatively) non-volitional.

In the second place, we know far too little of the anatomy and physiology of the cortex cerebri to regard it as being, as a whole, a volitional ganglionic centre, or as a single centre, at all. For all we can tell, the different layers of

the cortex may have functions almost, if not quite, as distinct from each other as are those of the thalamus opticus and the corpus striatum.

In the third place, the evidence that we should regard as essential to prove a movement to be of volitional or psychical type, namely, the fact of its association with other psychical events, such as sensations or other movements, we get in these experiments, somewhat, it is true (at least in the case of excitation of the sensory centres), but only very sparingly.

We do not mean to deny that lesions of the cortex in the neighborhoods indicated cause what might be called psycho-motor paralyses, as in aphasia, for example, but we maintain that in these pathological lesions parts are injured and connections severed of whose functions the electrical-irritation experiments of Hitzig and Ferrier, brilliant as they are, have taught us really but little.

The purpose of this criticism is not to detract from the importance of these experiments, but to show how they might, by this very brilliancy, lead physiol ogists to be content with but partial results, in other words, to object to the implied opinion that in obtaining certain coördinated muscular contractions by excitation of definite points of the cortex, we obtain more than a faint sugges tion of the essential function of the part.

The relation between the motor and the sensitive functions of the cortex cerebri might perhaps be symbolized to advantage by comparing them, regarded from the physiological stand-point, to two oblique cones, having a common base and diverging apices.

That portion of each cone which is common to both would represent the (psychological) region within which motion and sensation resign, in a measure, their individual characteristics to unite as the basis of thought.

The apex of the motor cone might represent the functions of the "motor centres" of Hitzig and Ferrier. But the essential and more numerous functions of the cortex, even that part anatomically included within these "centres," would be represented by the overlapping part of the cone, and the evidence is as yet very incomplete that the functions of this part can be studied through electrical excitation.

The recent valuable researches of Professor Munk of Berlin at once forestall and fortify this criticism in a measure.

According to them the so-called "motor region" of the cortex cerebri should rather be regarded as a region given up mainly to tactile perception, the movements being excited only indirectly, though, no doubt, through the medium of defined and specialized association-tracts.

While we take the liberty to doubt, on psychological grounds, the propriety of defining the functions of this or perhaps of any part of the cortex as purely sensory, it must be admitted that the views advanced by Munk are more broadly scientific than those of the uitra "localizationists," and so, perhaps, are also the views of those who hold, with Schiff, that the motorregion" is the seat of the muscular sense. J. J. P.

66

GEORGE B. WOOD, M. D., LL. D.

PROFESSOR GEORGE B. WOOD, whose name for more than half a century has been connected with medical teaching and medical literature, died on the 30th of March, 1879, at his residence in Philadelphia, having just completed his eighty-second year. A native of Greenwich, New Jersey, he was educated at the University of Pennsylvania, from which he received his medical degree in 1818. Four years later he became professor of chemistry in the Philadelphia College of Pharmacy, and in 1821 took the chair of materia medica in the same institution, which he resigned in 1835 to accept the same branch in the medical department of the University of Pennsylvania. In 1850, having been continuously connected with the latter institution in the position mentioned, he was elected professor of the theory and practice of medicine in the same school, and upon his resigning, in 1860, he was unanimously appointed emeritus professor of the theory and practice of medicine. In 1863 he was made a member of the board of trustees of the university, and in 1865 he instituted and endowed the summer school with an auxiliary faculty,' authorized to confer the degree of doctor of philosophy.

He was physician to the Pennsylvania Hospital for twenty-four years (183559), and was a member of the faculty of the University of Pennsylvania for about the same period. At the time of his death he was president of the College of Physicians of Philadelphia, and president of the American Philosophical Society. He was a member of a number of other societies, and had been president of the American Medical Association. During the last four years he had been an invalid and confined to his house, the last two years being unable to leave his couch.

The industry and zeal of Dr. Wood were such as to lead him, in former years, to contribute frequently to medical literature, but his reputation as a writer is chiefly based upon his Treatise on Practice, published in 1847, which ran through six editions, the last being in 1867. Previous to this work, however, he had, with the late Dr. Bache, compiled the Dispensatory of the United States, which first appeared in 1833, and is still extant, thirteen editions having been published. He also wrote a Treatise on Therapeutics and Pharmacology or Materia Medica (Philadelphia, 1856), and a number of addresses, including a short History of the Pennsylvania Hospital and one of the University of Pennsylvania.

The career of Professor Wood exemplifies in a striking manner the legitimate results of honest, earnest, persevering endeavor when associated with uprightness of character and unwavering integrity. Until the last, he preserved a warm interest in medical education, and by his death the University of Pennsylvania loses a warm and unselfish friend, and the profession of Philadelphia one of its brightest ornaments. He lived to see the maturity of many of his plans, and to enjoy the reward of his devotion to his chosen profession and to humanity.

The following were the chairs occupied in the summer school: (1) zoölogy and comparative anatomy, (2) botany, (3) geology and mineralogy, (4) hygiene, and (5) medical juris. prudence.

YELLOW FEVER ON THE PLYMOUTH.

THE bill authorizing the expenditure of two hundred thousand dollars in the construction of a steel refrigerating ship, according to the plan proposed by Professor Gamgee, passed the senate after some discussion, and so modified as to make its construction subject to the recommendations of the National Board of Health. Professor Gamgee proposes this as a steam vessel, to be used at the quarantine of such ports as may be recommended, to disinfect vessels and cargoes from ports suspected of infection with yellow fever and other contagious diseases. During the discussion a communication was read from Drs. Turner, Billings, and Hamilton, to the effect that the apparatus will give a probable temperature of zero F. to affect an empty ship throughout, but that it will probably almost always be necessary to discharge the cargo first; that the assumption that this temperature of a few hours' duration will destroy or render permanently harmless the yellow-fever poison has no facts as yet to sustain it; and that the project is an experiment worthy of trial.

The recent outbreak of yellow fever on board the United States ship Plymouth will render this proposition of Professor Gamgee's peculiarly interesting, and retard legislation upon his bill in the house of representatives until a full report has been made by the secretary of the navy. Upon the facts in the case, as called for by the house, resolution passed April 8th. The secretary has appointed Drs. Wm. T. Hord, Richard C. Dean, and Thos. W. Leach as a board to make a thorough investigation and report. The surgeon-general of the United States navy has furnished to the surgeon-general of the marine hospital service the following facts:

On November 7th last four cases of yellow fever occurred on board the vessel while lying in the harbor of Santa Cruz; these were removed to the hospital on shore, and the ship sailed for Norfolk. Three mild cases occurred during the voyage, and the Plymouth was ordered to Portsmouth, N. H.; thence to Boston. At the latter port everything was removed from the ship, and all parts of the interior were freely exposed to a temperature which frequently fell below zero, the exposure continuing for more than a month. During this time the water in the tanks, bilges, and in vessels placed in the store-rooms was frozen. One hundred pounds of sulphur was burned below decks, this fumigation continuing for two days, and the berth decks, holds, and store-rooms were thoroughly whitewashed. On March 15th the ship sailed from Boston southward; on the 19th, during a severe gale, the hatches had to be battened down and the berth deck became very close and damp. On the 23d two men showed decided symptoms of yellow fever, and on the recommendation of the surgeon the vessel was headed northward. The sick men were isolated, and measures adopted for improving the hygienic condition of the vessel and crew. The surgeon reported that he believed the infection to be confined to the hull of the ship, especially to the unsound wood about the berth deck, all the cases but one having occurred within a limited area; and that while the Plymouth is in good sanitary condition for service in temperate climates, should she be sent to a tropical station, probably no precautionary measures whatever would avail to prevent an outbreak of yellow fever.