' French National Institute, 303 



•essentially destined lo free the airimal body from the super- 

 abundance of this element. The two chemists in question, 

 although long occupied in studying this substance, ,only 

 procured it in its purity but very lately, and have conse- 

 quently madp a new display of the properties which they 

 found it to possess in this state. 



Here we ought to introduce M. Chevreuil's experiments 

 on indigo, and those of M. Thenard concerning the aitioii 

 of the vegetable acids on alcohol, as also the analysis of an 

 animal substance found in a grotto by M. Laugier; but as 

 these complex and troublesome labours do not yet leatl to 

 any genera! principle proper for being inserted in a report 

 of the present description, we are obliged to refer to the 

 memoirs themselves, which have appeared in the Aimnles 

 de Chimie, or in the Annales du Museum d' Histoire Na- 

 turelle. 



Among the subjects connected with anatoiny which have 

 occupied the attention of the class, the most interesting has 

 been a niemoir on the structure of the brain and of the 

 nervous svstem, presented by Messrs. Gall and Spurzheim, 

 physicians of V'ienna : these anatomists consider the cerebral 

 oroan in a verv difi'erent, and in many respects in a clearer 

 and more intelligiljjc light than hitherto adopted. Accord- 

 ing, to them the cortical is the oroan from which the ner- 

 vous fibres i.>*ue, which constitute the white or medullary 

 substance. Wherever this exists it arises from these fibres. 

 The spinal marrow is no longer a fasciculus of nerves de- 

 scending from the brain ; on the contrary, the nerves called 

 cerebral may be traced to the medulla elongata. The cere- 

 brum and cerebellum themselves are only develupmenu 

 of the fasciculi, coming from the medi,il!a elongata in the 

 same way as the nerves come from it: the brain in parti- 

 cular derives its origin from fasciculi called pyramidal emi- 

 nences, which cross each other, issuing from the medulla 

 tlongata, each of them proceeding towards the side oppo- 

 site to thiit from whicl) it issues ; they swell for the first time 

 when crossing the pons varolii,- a second time when pass-- 

 ing over the tubercles called optical layers, anda third time 

 in, those called corpora cavernosa, always by medullary 

 fibres furnished by the grayisli matter in these three parts, 

 adding to those which the fasciculi originally possessed, 

 and which there unite by acute angles, and thus ascend. 

 'l"he cerebelluni issues from fasciculi denonnnatedprocc'^izrf 

 ccreLelli ud mcdtdlam, which are reinforced, but once only, 

 by fibres furnished to them by the gray matter of what is 



called 



