Literary Notices. xxxix 



Descriptive anatomy offers less of interest than histology which, 

 especially in the case of the cerebellum, has taken long strides. The 

 Bericht has attained proportional extent, the present number occupy- 

 ing 67 closely printed pages and yet every reader will wish that some 

 subject had been treated more fully. 



c. L. H. 



The Peripheral Zone of the Cortex.^ 



It has been obvious to all who have carefully studied the cortex 

 that far too little attention has been given to its outermost zone. For 

 one thing it seems hardly to have dawned upon histologists that the 

 embryological stage when the cortex has a double proliferating zone 

 of cells at the periphery is of primary significance in understanding 

 later transformations. This fact is equally ignored or misunderstood 

 by embryologists. We are glad, therefore, that attention is now be- 

 ing directed to this field. 



Dr. Lewis recognizes two types of connective tissue structures, 

 (a) small cells (6-9 micra) with a proportionally large nucleus envel- 

 oped by scanty protoplasm scattered irregularly along the course of 

 blood-vessels, adjacent to nerve cells and in the brain substance ; (b) 

 larger cells (13 micra) of flask-like contour and abundant protoplasm 

 and having two kinds of processes ; first, such as are extremely radi- 

 ating and, second, coarse processes invariably attached to blood-ves- 

 sels by a sucker-like foot. The last mentioned cells stain very feebly 

 except in degenerate (paralytic) states. The vascular branch of these 

 (Deiters) cells is not subdivided. 



The author derives these from the primitive epithelial lining and 

 he believes that all " spider cells " pass through the three stages char- 

 acterized by, first, embryonic moniliform fibers, pertaining to epithelial 

 elements, second, true spider-cell features of vascular attachments, 

 third, fine stellate fibers of neuroglia. (It may be remarked in pass- 

 ing that in lower vertebrates the sustentive tissue can be traced very 

 easily to derivatives of the epithelial layer of spongioblasts.) The 

 transition from Andriezen's true neuroglia or stellate cells to the spi- 

 der cells the author claims to have clearly demonstrated. 



The tangential fiber belt is very rich in fibers which are not only 

 parallel to the surface but at times dip into deeper levels. Some of 

 the fibers can be traced long distances and give off collaterals at fre- 

 quent intervals to terminate in arborizations about pyramid cells. 



^ W. Bevan Lewis. The Structure of the First or Outermost Layer of the 

 Cerebral Cortex. Edinburgh Med. Journ., June, 1897. 



