CoGHiLL, Structure of the Nerve Cell. I97 



studied by de Buck and de Moor ('00). Their experiments con- 

 sisted in an examination of the lumbar cord after temporary and re- 

 peated compressions of the abdominal aorta in the rabbit for from five 

 minutes to one hour, and after permanent ligature. They find that 

 following a ligature of one hour no lesion can be discovered if the ani- 

 mal is killed immediately ; but if it survive for one hour and a half after 

 the ligature is removed, lesions are apparent. One-half hour is sufficient 

 period of ligature to cause a marked lesion. The chromatic elements 

 break up and ultimately disappear, leaving the cytoj^lasmic reticulum 

 in view. The nucleus is more resistive than the cytoplasm but finally 

 undergoes homogeneous atrophy. Lesions of this character are more 

 marked in prolonged, continuous ligature than in repeated, tempo- 

 rary ligature. In twenty-four hours after a ligature of an hour many 

 cells were found to be completely destroyed. To all these processes 

 the spinal ganglion cells are more resistant than the cells of the cord. 

 The authors conclude that these changes relating to the cytoplasm 

 cannot be considered as characteristic of anemia, for similar modifica- 

 tions arise from other causes, such as infectious diseases and toxins. 

 The nuclear changes, however, they think, may be characteristic. 



Van Gehuchten's earlier position regarding the lesion of the 

 nerve cell resulting from section of the axone was that all such cases 

 were followed by chromatolysis in the cells of origin. His more re- 

 cent work ('98), however, leads him to the conclusion that section, or 

 ligature, or a nerve will not always 2:)roduce chromatolysis in the cells 

 of origin. He observes such a case in the section of the sciatic nerve 

 of the rabbit, in which case the cells of origin are found in the pykno- 

 morphic condition but not in a state of chromatolysis. This condition 

 he attributes to the traumatism. Later researches, in collaboration 

 with VAN BiERVLiET ('oo), couvincc VAN Gehuchten that the lesion 

 of the cell of origin following injury to the nerve varies both according 

 to the intensity of the injury and according to the nerve involved. 

 The cranial nerves appear to be much less resistant than the spinal 

 nerves. The authors conclude also that the cell of origin which is 

 affected by section of the axone may recuperate without regeneration 

 of the axone. 



Regarding the comparative cellular lesion which follows mere sec- 

 tion of the nerve and extraction of it, de Beule has experimented 

 upon the rabbit by extracting and sectioning the hypoglossal nerve. 

 The cells of origin were examined at from one to thirty-five days after 

 the operation. He found that on the fourth day the cells were still 

 increasing in size, but on the sixth day they had begun to grow smaller. 



