Dr. Foville's Researches on the Anatumij of the Brain. ^37 



which may accrue to the science of medicine from a more ex- 

 act knowledge of the anatomy of the brain, than to make known 

 those which I have myself derived from it. 



Recapitulation. 



The crus cerebri is composed of two bundles of fibres ex- 

 panded in the corpus striatum and thalamus nervi optici into a 

 larger plane, which radiates from the crus, taken as the centre, 

 towards the hemisphere regarded as the circumference. This 

 plane, which we may consider as the origin of the different parts 

 which follow, is divided into three secondary layers or planes, 

 having an arrangement which may be compared to three pe- 

 tals of an Iris held together between the fingers, two of the 

 petals turning their concavity ujnvards, and the third turning 

 its concavity downwards. 



The superior of these planes forms with its fellow the corpus 

 callosum, which may be regarded as the commissure of the 

 crura. The middle plane belongs exclusively to the hemisphere, 

 and the inferior belongs to the septum lucidum, the temporal 

 lobe, and the cornu Ammonis. 



The central parts of the brain present in their structure a 

 striking analogy to the spinal cord, and, as I believe, ought to 

 be considered as its superior termination ; an opinion which 

 has already been adopted by many authors. 



The plane of the hemis])here I consider to be analogous to 

 the spinal nerves ; and the cineritious matter of the convolutions 

 I regard as constituting the essential part of the cerebrum. 



These anatomical data appear to lead to several physiolo- 

 gical probabilities, which pathological observations appear to 

 confirm. 



Finally, I conceive that the knowledge of the structure of 

 the brain, such as 1 have pointed it out, may be found of real 

 advantage in the detection of the morbid alterations of which 

 this organ may be the subject. ^ Foville. 



[This Memoir was presented to the Institute on the 24th of March 1828.] 



After the analysis the Report proceeds. — The principal fact 

 which the author brings forward, and which tends more and 

 more to })rove, that within the assemblage of the vertebrae of 

 the head, the nervous system is composed of a central part, 

 the prolongation of the spinal marrow, and of ganglia ; and 

 further, tiiat the crus cerebri is composed of three planes or 

 orders of fibres, one of which passing inwards forms the corpus 

 callosum, appears to us to be placed beyond a doubt, at least 

 with respect to the human subjeot. We must, however, confess 



S.S. Vol. '>. No. 29. Mai/ IS'^f). 'J X tlial 



