I.

Conclusions.

The groups of mated rats grew to be somewhat heavier than the unmated groups. This was found to be true in four out of the five groups, Group A being the exception (see note, p. 521). The mated individuals were, on the average, 9 % heavier than the unmated.

2. The mated rats had both absolutely and proportionately the heavier central nervous systems.

3. The weight of the brain, in the mated rats, was however not so heavy as we should have expected from the body weight. Assuming that the brain weight should increase among mature rats in proportion to the—of the body weight1 and taking the unmated rats as the standard, we find that the brain weight observed in the mated rats would correspond to a body weight of 219.5 gr. But the observed body weight is

226.2 gr. We draw the conclusion that the mated animals were somewhat fatter than the unmated-a conclusion which harmonizes with the facts observed at autopsy.

4. The spinal cord was disproportionately heavy in the mated groups. From the laboratory records of breeding females of about the same weight, it appears that one gram of increase of body weight is accompanied by .0020 gr. of increase in the weight of the cord. If we take the relation between the

the

'DuBois found that in man at maturity the brain weights were related as

of the body weights. DHÉRE and LAPICQUE, have determined a like relation in dogs of different sizes.

increase in the body weight of Groups B and C as compared with D and E (A being omitted: see note p. 521) of both the mated and unmated series, we find that in this case the increase of one gram of body weight is accompanied in the mated series by .0032 gr. and in the unmated series by .0012 gr. increase in the weight of the cord or on the average by .0022-nearly the value found from the laboratory records. If, then, we consider that the removal of the excessive fat on the mated series would reduce its body weight to 219.5 gr. when the animals were in the same condition as the unmated series, then the difference in body weights between the two series amounts to 8.7 gr. which would call for .0191 gr. additional cord weight in the heavier animals. The observed difference in the two series is .6317-6025 gr., or .0292 gr., which serves to show that the spinal cord of the mated rats is heavier than we should expect from their true body weight. Whether this excess has resulted from changes affecting the entire cord or only the lumbar regions, was not determined.

5. The brain and spinal cord of the mated individuals contained a slightly higher percentage of water. Only a single exception to this relation was found in the entire series of ten groups, namely in the case of the spinal cord in Group C.

6. In general the older groups had smaller brain weights than the younger. The diminution in brain weight according to age is nearly proportional in the mated and unmated groups. This change probably marks the beginning of senescence.

Résumé.

The effect of the bearing of young is to render the mated rats slightly heavier than the unmated-some of the excessive weight being due to the larger amount of fat present in the mated animals. The proportional brain weight is not appreciably affected, but the spinal cord is distinctly heavier in the mated series, thus making the central nervous system as a whole heavier. The percentage of water in both the brain and spinal cord is in nine cases out of ten greater in the mated groups. This is perhaps the most important difference estab

lished by the foregoing investigation, but the interpretation must await a further study of the diminution of the percentage of water in the central nervous system with advancing age and the conditions which probably modify it.

Bibliography.

Dhéré and Lapicque. '98. Sur le rapport entre la grandeur du corps et le developpement de l'encéphale. Archives de Physiologie, No. 4.

DuBois, '98. Ueber die Abhängigkeit des Hirngewichtes von der Köpergrösse beim Menchen. Archiv f. Anthropologie, 25.

Edlefsen, '68. Ueber den Einflus der Schwangerschaft auf das Wachstum und des Wachstums auf Zahle und Gewicht der Jungen nach Beobachtungen am Meerschweinchen. Arbeiten aus dem Kieler Physi

ologischen Institut.

Gassner, '52. Ueber die Veränderung des Körpergewichtes bei Schwangeren,

Gebärenden und Wochnerinnen.

Frauenkrankheiten, 19.

Monatsschrift f. Geburtskunde u.

Hensen, '68. Anhang zur Arbeit von Dr. EDLEFSEN. Ibid.

Minot, '91. Senescence and Rejuvenation. Jr. Physiology, 1, No. 2.

EDITORIAL.

THE WORK OF CARL WERNICKE.

In the death of Carl WERNICKE last spring the world lost one of its greatest students of the form and function of the human brain. Comparatively a young man, only fifty-seven, WERNICKE, as a result of an accident, met with while holidaying in the forest of Thüringen, was cut down at the height of his professional activity. The revision of his text-book on psychiatry, one of the most original and inspiring of modern works on the subject, occupied him just previous to his demise.

As a teacher, WERNICKE attracted many students to work under him personally; he reached more through his published articles and books. As a personality, he possessed originality, independence and fearlessness, and accordingly came into conflict, sometimes bitter, with the opinions of other individuals of his time. As an investigator he leaves behind him a record of discoveries which will preserve his name permanently in the histories of brain-anatomy, brain-pathology, clinical neurology and psychiatry.

His life from his graduation on was devoted consistently to farthering progress in our knowledge of the brain. He began with brain-pathology, perfected himself in brain-anatomy, and did his best work in clinical observation.

Students of cerebral anatomy know WERNICKE especially through (1) his study of the gyri and sulci of the cortex cerebri, (2) his presentation of the microscopic features of the fibrebundles of the brain as a whole, and (3) his atlas of brain-anat-omy. He enriched our knowledge of cerebral topography by observing in the maze of sulcus variation the constants now designated as the sulcus occipitalis anterior, the sulcus occipita

lis inferior and the sulcus fronto-marginalis. His contribution to the microscopic anatomy of the brain consists chiefly in his thorough presentation with valuation of the view points of embryology and phylogeny, of the totality of fiber-bundles, based upon the studies of MEYNERT, GUDDEN and FLECHSIG.

WERNICKE'S cerebral pathology was based upon anatomy and physiology. Indeed it is in the first volume of his "Diseases of the Brain" that his systematic description of microscopic anatomical structures is to be found; this first volume is a collective review which may well serve as a foundation for all who desire to begin the serious study of the complexities of the cerebral conduction paths. His greatest single contribution to the pathological physiology and anatomy of the brain, was, undoubtedly, the discovery of the so-called "sensory aphasia” and the definite localization in the pallium of the area, diseases of which calls forth that now well-known and generally recognized syndrome. Studies in brain-histology proper seem to have interested WERNICKE much less than studies in gross and microscopic anatomy. Accordingly one finds, but little mention of intraneuronal features in his writings. It was the grouping and chaining-together of neurones in greater complexes with formation of 'centres' and conduction-paths which appealed to him most, as was natural, perhaps, in a man so profoundly interested in cerebral localization and in the problems of aphasia and psychiatry as WERNICKE was.

The study of the aphasic symptom-complex which WERNICKE published in 1874 stands as an important pillar of support to modern clinical neurology. It was a research which ranks with the earlier studies of BROCA and SAX. It had not only a great neurological significance but exerted, through the analysis of the cortical processes which it embodied, an important influence upon the conceptions of physiological psychology. The demonstration of the continous process:-stimulus, sensation, memory-picture, association with other memory-pictures and motor projection, was first brought, as ZIEHEN points out, by WERNICKE, though the principles upon which it is based may be found in the investigations of others.