484 GENERAL ANATOMY. 



flammation in different degrees, of chronic inflammation; acute 

 and chronic hydrocephalus are also met with. The affections 

 of the nervous substance, may be complicated by those of its 

 membranes. 



The affections of the spinal marrow are more rare in man 

 than those of the encephalon ; the contrary takes place in 

 animals. 



These different alterations, according as they are acute or 

 chronic, according as they act by irritating, by destroying, or 

 by compressing, and according to their seat, bring on different 

 derangements more or less serious, in the functions of the nerv- 

 ous system. 



768. The nervous tissue is not produced accidentally ; the 

 affinity established between this tissue and the encephaloid 

 production, by Maunoir, rests upon insufficient analogies. 



The nervous tissue on being wounded cicatrizes, when the 

 wound is of such a nature as to permit the individual to sur- 

 vive. 



Wounds of the encephalon, and of the spinal marrow, when 

 they are not mortal, unite like those of other parts. Wounds 

 of the encephalon, with loss of the substance of its envelopes, 

 heal by the formation of an exterior cicatrix. This fact has 

 been observed by Dumeril, in salamanders, and by many sur- 

 geons, in the human species. Wounds with loss of the sub- 

 stance of the brain, the cranium remaining entire, heal by the 

 formation of a new substance, soft, mucous like, which does 

 not altogether resemble that of the organ, and by the enlarge- 

 ment of the corresponding ventricle of the brain. Tearing of 

 the encephalon, produced by sanguineous extravasation, pre- 

 sents, when the individual survives, remarkable phenomena. 

 The blood is soon surrounded by a layer of organizable lymph; 

 this layer becomes vascular and unites with the nervous sub- 

 stance; the blood is gradually absorbed, or at first the fibrine 

 and the cruor, and then there remains the serum;* or at first 

 the serum, and then there remains a fibrinous coagulumt to 



* Riobe, Observations propres a rtsoudre cette question: Vapopkxie, &c., 

 est-elle susceptibk de gueriaon? Paris, 1814. 

 f Rochoux, Recherches sur Papopkxie; Paris, 1814. 



