STRUCTURAL ALTERATIONS IN NERVE CELLS 205 
evidence adduced to show that one factor concerned in tlieir production is the cutting off' of the 
afferent impulses whicli normally innervate the anterior cornual cells by means of the reflex 
collaterals of the posterior roots. 
(iii) NissL* in 1892 introduced his method of staining nerve cells by methylene blue, and 
stated that in so short a period as 24 hours after division of the trunk of the facial nerve an 
alteration in structure could be found in the corresponding nucleus. The changes described by 
NissL may be thus summarized : — After 24 hours the blue bodies may be seen to undergo an 
alteration at one point in the cell which consists in a loss of their distinctive shape and arrange- 
ment, and a dispersion over the body of the cell. In from 2 to 3 days this change spreads all over 
the cell. The Nissl bodies become paler, and ultimately take the appearance of minute specks of 
colouring matter. On the fourtii day the whole cell is swollen and more globular, and the 
processes are homogeneous. On the sixtli day the cells appear as if uniformly covered over with 
the finest coloured particles, and the processes have disappeared. The nucleus passes towards the 
periphery and finally disappears. The change takes place with greater rapidity in some cells than 
others, but the i8th day all the cells in tlie nucleus are thus broken up. 
NissL speaks of these changes as produced by a ' Mcthode der primiiren Rei-zung,' and 
regards his observation as having established the fact tliat the cutting off" of a nerve cell from its 
end organ calls forth repressive changes in the cell in fully grown animals. 
A number of observers have confirmed and extended tiiis observation. Van GEHUCHTENt 
describes and figures changes in the oculomotorius nucleus produced three days after section of the 
third nerve in the orbit. Bach,J Flatau,§ Bernheimer,|| and SchawbeU have utilized the 
method as a guide to the localization of the diff'erent groups of cells which compose the 
oculomotorius nucleus. Marinesco** also and Fleming tt have obtained similar results, and 
LuGARoH has figured changes in the spinal ganglion cells as a result of section of the sciatic nerve. 
Llewellys Barker in a recent paper refers to this subject, and figures markedly altered cells 
obtained by Erlanger in the case of the facial nucleus after section of its nerve trunk. My own 
observations have been made in the condition of the spinal cord after section of an anterior root, 
of the oculomotorius nucleus after intracranial division of the third nerve, and of the facial nucleus 
after division of that nerve at tlie stylo-mastoid foramen. 
Section of an anterior root. The cauda equina of a Cat was freely exposed by opening up 
the dura mater, a posterior root pushed aside and the corresponding anterior root severed near the 
spinal ganglion. |{{| The same precautions as mentioned in the cases of division of the posterior roots 
were taken. A post-mortem dissection showed that in eacli of three instances the seventh post- 
thoracic root had been divided and the completeness of the section was confirmed by the presence 
* Nissl. ' Zeit. f. Psych.,' 48, p. 675. 1892. ' Centralb. f. f[ Schawbe. ' Neurol. Centralb.,' p. 792. 1896. 
Nervenheilkunde,' xvii, p. 337. 1894. ** Marinesco. ' Revue Neurologique.' Mar. 15, 1896. 
f V. Gehuchten. ' Systeme Nerveux.' 1896. ff Fleming. ' Brit. Med. Journ.' Oct., 1896. 
X Bach. 'Arch. f. Nervenheilkunde,' 32, p. 16. \X Lugaro. ' Rivista di Patologia nervosa e Mentale,' 
^ Flatau. ' Fortschritte der Medicin,' 14. 1896. p. 457. 1896. 
II Bernheimer. ' Wien. Klin. Wochenschrift.' Jan, 30,1890. Barker. ' Brit. Med. Journ.' Dec. 25, 1S97. 
nil Onufrowitz ('Journal of Nervous and Mental Diseases,' 1895) has also studied the condition of tlie spinal cord in the 
lower dorsal region after division of an anterior root. He used vcsuvin for staining and found changes sonieu hat similar to those 
now described by myself. 
