Morphology of the Cerebral Convolutions, with Special Reference to the Order of Primates
Boston Medical and Surgical Journal
a descendant of Dolor l;avis, one of the first settlers on the Cape. His early education was obtained in the common schools. In 1835 he visited a sister under treatment for lateral curvature of the spine ; and on inquiring about the treatment, it seemed to him unphilosophical and ill adapted for the desired end. He ascertained that this was the best treatment known to the profession. This decided him to begin the study of medicine, and to devote himself to this department of surgery. In the
... surgery. In the winter of he attended lectures at New Haven, and was under the instruction of the professor of surgery. The next spring he went to Bellevue Hospital. He graduated from the Yale Medical School in March, 1839, practised in Worcester a short time, and then went to Millbury, where he treated a large number of patients from the surrounding towns. In 1855 he left Massachusetts for New York City. Here he treated patients from all parts of the United States and from abroad, and also wrote a book on diseases of the thigh and hip. He was the inventor of several ingenious appliances. He was a man of ideas rather than of scholastic attainments, and as such disregarded erroneous traditions of the past and opened a way to the great advance made in America, especially in the study and treatment of hip disease. He leaves three children, a son and two daughters. There is nothing which shows more clearly than the history of our knowledge of the topography of the cerebral cortex that the progress of science is not due solely to improved means of observation, as is, of course, true, for instance, of all microscopic anatomy, but also to more logical, comprehensive and systematic methods of thinking. Material for exactly such observations as are made in this essay has been freely accessible for centuries, and required no further means of observation than a pair of ordinary eyes ; yet even so recent a writer as Ecker speaks of the artists who drew the convolutions of the brain as they might do any dishful of macaroni as not in the far distant past. In fact, we might say that almost the whole, of this science is a growth, not only of the present century, but of the last three-quarters thereof. The mapping out of the surface of the human brain in an arbitrary way, so that any given convolution may be accurately described and located, may be regarded as now practically accomplished. This kind of description, however, has never seemed satisfactory to many students, anil numerous attempts have been made to make this art of cerebral morphology more coherent and systematic by theories of the methods by which the infolding of tho cortex takes place. Dr. Parker's essay is the most recent, and perhaps the most successful of these. It discusses minutely the convolutions in the brain of several raceswhite, negro and Chinese in the human fetus nnd in many species of monkeys and other lower animals, a large number of the figures being original. These, of course, cannot even be. indicated in a notice of this length; hut some of the general conclusions may be quoted, as showing the character of the work. " 4. The occipital lobe as a wholo is formed by a regular Ruroll-liko infolding around tho fissure of the posterior horn of the lateral ventricle, the calcarla«. " From this single, symmetrieally-dovoloped occipital lobo eight convolutions separated by six tissures p;iss forward t" tho two anterior extremities of the divided cerebral hemisphere. Theso are split by the Sylvian fissure into two groups, equal In the number of fissures and convolutions composing them, and similarly related, an oeeipito-frontal and an occipito-temporal lobe. " Of those two lobes the oeeipito-tomporal always retains its primitive simplicity ; but the oeeipito-frontal group, owing to its greater anterio-postorior extension, is exposed to pressure forces that tend to produce a vertical fissuration, as a result of which we have the production of the fissura eentralis with its vogetative repetitious, the post-central and preeeutral lissures in tho parietal region, whilst anteriorly the type remains unchanged. " In tlie primates each hemisphere, with respoet to its convolutions, is a symmetrical bud, arranged around the point of entrauce, the cerebral erus; its posterior portion involuted in a regular and symmetrical manner around the fissure of the posterior bom of the lateral ventricle (fissura calearina), whilst the anterior portion is split by the fissure of Sylvius into two symmetrical halves, consisting of the same number of fissures aud eouvolutions iu each divisiou. Of these the oeeipito-frontal division or lobe is related to the upper brauch of the fundamental mesial arched fissure (fissuracallosalis), and the occipitotemporal in a corresponding manner to the inferior brauch (fissura hippocampi). " Viewed in this way, the arrangement of the convolutions in man and the Simiadre becomes so clear, that at a glance one can see, recognize and remember the entire cerebral conformation of any individual brain that may be under examination, and auy special peculiarities that may exist at once become marked and prominent. Without the aid of this morpliie conception the cerebral surface presents a confused mass of isolated convolutions, lobules, fissures, sulci and sulculi, which it is impossible to put together as a whole. . . . "Like other organic buds, the cerebral hemispheres develop symmetrically, and the type of fissuration is due to the resultaut forces produced by the interaction of the growth forces of the hemisphere combined with the pressure forces of the less rapidly expanding but symmetrically developing cavity of tho skull. . . . " The question as to which of these two series of forces is most potent in its differential actiou in producing fissuration it is hard to answer ; but it would appear that in the earlier, and even to the quite late, stages of development it is the brain which modifies the shape and structure of the skull rather than the reverse, aud that finally, as the skull grows more and more rigid, its influence is showu by the increasing tortuosities and pushing out of place of previously existing parts." It may be noted with some satisfaction that the views and arrangement of Dr. Parker interfere but little with the nomenclatures at present in use. The essay closes with an ingenious application of the laws of the formation of partitions formed by spherical liquid films such as are formed by the meeting of two or more soap-bubbles, the expanding liquid films representing the expanding cerebral substance as it aggregates around certain centres of growth. This notice is written, not as an appreciative review, but to call the attention of the anatomist and neurologist to a work that as yet has received but little recognition, that is, within the notice of the present writer. R. T. E.