196 HANSFORD MACCURDY 



observations of Friedlander und Krause ('86) showed that altera- 

 tions in the roots of the severed nerve were considerable. In 

 long-standing cases of amputations, these authors reported altera- 

 tions of medullated fibers, and a reduction in the size of the bun- 

 dles of fibers. These observations led to experiments on animals 

 for more direct evidence on the questions involved. Homen 

 ('90) performed experiments by cutting nerves in a number of 

 dogs and found that the cells of the related ganglia were much 

 reduced in size. He attributed this reduction to atrophy of the 

 ganglion cells and their nerve fibers. Krause ('87) expressed the 

 opinion that true retrograde degeneration is identical with Walle- 

 rian degeneration. Marinesco ('92) found that on cutting the spi- 

 nal nerves marked changes occurred in the dorso-lateral group of 

 cells in the spinal cord, and stated that the number of these cells 

 was much less in animals operated upon than in the case of nor- 

 mal animals. He also claimed that the remaining cells showed 

 more or less atrophy. In experiments in which the ganglion nodo- 

 sum was concerned, he (Marinesco, '98) described a period of 

 restoration after the period of depression. 



Fleming ('97), operating on dogs and rabbits, measured the 

 nuclei of the affected nerve cells and at the end of 12 days found 

 them to be smaller than the nuclei of normal nerve cells. At the 

 end of eighteen weeks, he found still greater differences in the 

 size of the affected and normal nuclei and the noted some atrophy 

 and the disappearance of some cells. He also described differences in 

 the size, position, and arrangement of the chromatic elements 

 in the cells. In experiments on rabbits. Van Gehuchten ('97) 

 found the majority of the ganglion cells of the ganglion nodosum 

 degenerated. Similar results were obtained from the dog by 

 Kosaka und Yagita ('05). Koster ('03) gave an account of a 

 series of experiments on cats, dogs and rabbits in which the sciatic 

 nerve was cut near its exit from the vertebral canal. He described 

 differences in the tigroid bodies of the spinal ganglion cells. In 

 some of the cells a partial restoration occurred, while in others 

 complete degeneration was found. A modification of the tigroid 

 substance of the cell protoplasm was found to take place four 

 to six days after the operation, while degeneration occurred only 



