OF THE NEKVUS OCTAVUS. . 47 



regards , the method is giving too much , and is dangerous espe- 

 cially if the atrophy existed for a long time. 



These objections to GUDDEN'S method have discredited it , and 

 in modern investigations the method of secundary degeneration , as 

 it was used by MARCHI, is preferred. 



To be sure , MARCHI'S method is giving results in cases , wherein 

 that of VON GUDDEN is impracticable. 



Degenerated fibres distributed between intact fibres are easily 

 found. When the method is used within a fortnight after the ope- 

 ration , the black granules in the degenerated fibres may be strictly 

 limited to the damaged and degenerated system. Nevertheless grave 

 objections are also to be made to the MARcm-method. 



l ly . There must be certainty, that the experimental lesion, which 

 is studied with MARCHi-tinction , has passed without any complica- 

 tion. A slight infection, the most superficial meningitis, etc. may 

 be the cause of such an abundant overflowing of black granules 

 in the nervous system , that all the results of the experiment are 

 disturbed. 



2 ly . The black granules do not remain strictly limited to the 

 degenerated fibres , where they orinigated. The existence of neuro- 

 phagic cells transporting the myelin-globules into the lymph-channels 

 and the lymph-fissures is a grave complication. The black granules 

 therefore are often found in places, independent of the original 

 focus of degeneration. SUCH for instance is the case, in nearly all 

 the roots of periferical nerves. Their entrance in the medulla 

 oblongata is the favorite spot , where black granules are found. 

 For instance , black granules are nearly always found at the entrance 

 of the III d nerve , consequently to every operation made in the 

 oblongata or in the pons Varoli. 



The quantity of the transported granules is increased in reason 

 of the time that has passed after the operation. 



3 e . Every small incision made in the central system , is surrounded 

 by a (in MARcm-tinction) white coloured mass, without black gra- 

 nules. The white-coloured mass in the neigbourhood of the wound 

 must be added to the extent of the lesion. 



4 e . The existence of the so called retrograde degeneration studied 

 by VAN GEHUCHTEN and others. The retrograde degeneration (from 

 the body of the cell , which axon was sectioned towards the section) 

 begins after a fortnight. 



5 e . Three weeks (and even earlier) after the operation , the dege- 

 neration in the sectioned system is complete. The degenerated fibres, 

 though they may end in the nuclei by unfolding their terminal 



