REGENERATION OF THE NERVOUS TISSUE. 



585 



FIG. 187. Corpora amylacea. (Funke.) 



the substances are, in greatest part, peculiar to the nervous tissue, and that they contain 

 phosphorus, we have stated about all that is physiologically important. Lecithene is a 

 neutral phosphorized fat, probably composed of a number of different fatty principles, 

 which exists, not only in the nervous substance, but in the blood, bile, and the yolk of 

 egg. Its chemical history has no physiological interest. It is said to be identical with 

 protagon (Robin). The same may be said of cerebric acid, the cerebrate of soda, of oleo- 

 phosphoric acid and its compounds with soda and lime. 



Corpora Amylacea. Little rounded or ovoid 

 bodies, about y^V^ of an inch in diameter, have 

 been described by Virchow and others as exist- 

 ing normally in the corpora striata, the medulla 

 oblongata, and in some other parts of the cere- 

 bro-spinal system. With regard to the actual 

 composition of these bodies, there is considera- 

 ble difference of opinion. Virchow and many 

 others regard them as identical with starch, the 

 granules of which they certainly resemble very 

 closely, being of the same shape, with borders 

 well defined, frequently presenting concentric 

 laminsB and a hilum. When carefully treated, 

 first with a solution of iodine and then with a 

 little sulphuric acid, they assume a blue color. 

 Some observers consider them as analogous to 

 cellulose, others have supposed that they are formed of cholesterine, and others regard 

 them as nitrogenized bodies. These points are of purely anatomical interest, and the 

 physiological relationg of these bodies are not known. 



Regeneration of the Nervous Tissue. 



We do not propose to discuss fully the question of the regeneration of nerves after 

 section or even excision of a portion of their substance, although it is one of great patho- 

 logical interest; but, in this connection, we shall refer to some experiments recently 

 made, in which it appears that it is possible for certain of the most important of the 

 nerve-centres to be regenerated and their function restored after extirpation. 



With regard to the simple reunion of nerves after division or excision, it has long 

 been known that this takes place in the human subject and in the inferior animals, with 

 restoration of function. The new tissue connecting the divided extremities of the nerve 

 seems to pass through the regular stages of development observed in the nerve-tissue of 

 the embryon, the gelatinous fibres, or the fibres of Remak, first appearing, and these 

 being subsequently developed into true nerve-tubes. In this process there is not a cica- 

 trix, as in the skin or muscular tissue, but a development of new elements possessing the 

 anatomical and physiological characters of the original structure. 



A point of considerable physiological interest connected with the regeneration of the 

 nervous tissue is involved in the recent observations of Voit upon the regeneration of 

 the cerebral lobes after removal in a pigeon, and in those of Masius and Vanlair upon the 

 anatomical and functional regeneration of the spinal cord in frogs. 



The experiments recorded by Voit, and his deductions, are very curious and have 

 given rise to a great deal of comment and criticism. In one observation, the cerebral 

 lobes were removed from a young pigeon in the usual way, an operation very easily per- 

 formed, and one which we practise yearly as a class-demonstration. It is particularly 

 stated that the operation was complete, and that the entire posterior lobes were removed. 

 Immediately after the operation, the pigeon presented the condition of stupor ordinarily 

 observed. As he gradually recovered from this condition, he began to execute a number 



