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6 



LEONOWA'S RECENT OBSERVATIONS ON THE 

 ANENCEPHALIC AND AMYELIC NERVOUS 

 SYSTEM. ' 



C. Judson Herrick. 



A few years ago Professor v. Leonowa of the Anatomical 

 Institute at Moscow contributed a full description of the central 

 nervous system of an anencephalic human infant. 1 The spinal 

 cord was present and a very small part of the medulla, the lat- 

 ter terminating at the superior or sensory level of the decussa- 

 tion of the pyramids. In spite of the absence of the respiratory 

 centre, the child lived ij hours, 20 minutes. Microscopic ex- 

 amination of the cord showed a diminution of the number of 

 the ganglion cells in the gray matter, a greater or less micro- 

 myelous condition of the white tracts and the total absence of two 

 bundles; viz., the antero-lateral pyramids and the direct cere- 

 bellar tracts. The latter point of course is correlated with the 

 absence of the cerebrum and the cerebellum and implies the 

 downward, or centrifugal growth of these tracts. 



More recently the same author has described 2 another case, 

 a foetus of eight months about 34 cm. long, which was both 

 anencephalic and amyelic and which presents so many points of 

 general interest that we give here a full abstract of the paper. 



Microscopic examination showed total rachischisis along the 

 whole length of the vertebral axis, skull represented only by 

 the base, without the cranial vault, the base containing a red- 

 dish, shapeless mass which v. Recklinghausen has called "sub- 

 stantia medullo-vasculosa, " the lateral and superior parts of 



'Leonowa, O. v. Ein Fall von Anencephalic Archiv f. Anat. u. Phys., 

 1890, Anat. Abth., pp. 403-422. I plate. 



2 Leonova, O. v. Contribution a l'etude de revolution pathologique du 

 systeme nerveux. Anencephalie totale combinee avec une amyelie et un rha- 

 chischisis totaux chez un embryon humain. Bulletin de la Societi Imperiale des 

 Naturalistes de Moscou, 1893, No. 2-3. 



