516 THE BRAIN OF MAMMALS, BY TH. MEY.NEKT. 



careful investigation by Gerlach, presents the closest similarity 

 to the granule layers found in the olfactory lobes. Its elements, 

 on account of the protoplasm surrounding them being extra- 

 ordinarily delicate and destructible, appear in the form of very 

 minute naked granules, measuring 6 /*, respecting which a 

 threefold interpretation has been given. Gerlach and Kolliker 

 believed that they saw in them a cluster of elements belonging 

 to the connective substance, which Gerlach nevertheless allowed 

 to be enclosed by the internally directed processes of the .large 

 nerve cells. Henle and Merkel look upon them as lymph 

 corpuscles. Stilling regards them as an extremely small 

 variety of multipolar nerve corpuscles, connected with each 

 other in a reticular manner. Their protoplasm, which is often 

 enough distinctly marked, and gives off several processes that 

 do not very frequently branch (fig. 235, e), is sharply denned, 

 and of a hyaline clearness in the cerebellum of the newly born 

 infant (where they have been shown to me by my colleague, 

 M. Fries, of Vernek), in consequence of which these elements 

 strongly resemble the inner granules of the retina. 



The medulla of the cerebellum contains, in the medullated 

 laminae of the convolutions, numerous granular elements which, 

 in part at least, are emissaries of the granule layer. A consi- 

 derable proportion of them, however, are to be regarded as 

 connective-tissue elements. I have arrived at a positive con- 

 clusion on this point on account of the pathological changes to 

 which I have referred at p. 385, and which repeat themselves 

 in the medulla of the cerebellum. 



According to Stilling, the fibres of the medulla of the cere- 

 bellum, in opposition to the conditions requisite for isolated 

 conduction, are everywhere connected with each other in a 

 plexiform manner. This course, which has not been corrobo- 

 rated by any other observer, can only have been supposed to 

 occur by confounding a connective-tissue reticulum with the 

 nervous elements, owing to that haziness of the image with 

 which the remains of the altered medulla cover and conceal 

 the arrangement of the elements in sectional preparations that 

 have not been rendered thoroughly transparent. Stilling 

 himself raises an important objection to his own statement 

 when he describes, notwithstanding the supposed connection 



