338 Dr. Foville's Researches 07i the Anatomy of the Brain. 



that we have not been able to see so clear a demonstration in the 

 brains of some of the mammifera which we have examined*. 



We are thus compelled on this point to renounce the opi- 

 nion of Drs. Gall and Spurzheim, who consider the corpus 

 callosum as composed of converging fibres, and forming the 

 commissure of the two hemispheres. We may assure our- 

 selves of the state of the case by a very simple process. It 

 consists in separating the two hemispheres from above, and 

 gently passing the finger under the edge which the flat ver- 

 tical surface presents to the corpus callosum, into what has 

 sometimes been called the ventricle. We thus readily arrive 

 at the line of separation between the two upper planes, one of 

 which passes inwards, and the other vertically upwards, into 

 the hemisphere. It appears to us, however, that it is impos- 

 sible to make this separation without some rupture taking 

 place between the two parts ; but this may possibly depend on 

 strong adhesions occasioned by the disorganization of the mem- 

 brane of separation. We may likewise easily show these dif- 

 ferent planes by making the vertical section above described, op- 

 posite to the situation of the coronal suture, through the brain 

 of a young infant. We may even perceive between the two 

 inferior planes a trace of cineritious matter, pointing out their 

 separation ; and by merely blowing on them at this part, we are 

 sometimes able to effect their detachment from each other. 



We consider this part of Dr. Foville's paper as worthy of 

 the utmost attention of the anatomist. We think that the idea 

 of regarding the middle plane of the crus cerebri as analogous 

 to the nerves of the spinal marrow, and as losing itself in the 

 cineritious matter of the convolutions, is happy,and in harmony 

 with what we know of that part of the ganglionic nervous 

 system which is furnished with external apparatus. It is also 

 corroborated by the anatomical observations of Dr. Foville. 



It appears to us that the course which this anatomist has 

 taken is the only one which can lead to any certain results ; 

 since he makes his anatomical and pathological researches 

 keep pace with each other, and has already begun to syste- 

 matize some parts in the anatomy of the brain, in conjunction 

 with its functions both in the state of health and disease. In 

 this attempt he has, perhaps, been more successful than any 

 one who has preceded him. 



But as we know that this anatomist has already obtained 

 an insight, perhaps equally interesting, into other important 



* Since this Report was written, I have had the advantage of seeing the 

 brains of several of these animals examined by Dr. Foville; and witli the 

 precautions which he had then employed, llic existence of the three planes 

 was most readily and satisfactorily shown, althougii, as Blainville remarks, 

 this point was at one time not so easily effected. — T. H. 



parts 



