Nov. 1, 1919 Pathology of Dourine 149 



evidence of degeneration. Staining with the Marchi method showed 

 very light-brownish or yellowish coloration of the myelin and no black 

 deposits. This differential action of osmic acid results from the fact 

 that chromic acid and its salts deprive the normal myelin sheaths of their 

 power of reducing osmic acid, while the chemically changed degenerating 

 or abnormal sheaths retain this power. The method therefore gave posi- 

 tive black images of fibers in a state of degeneration, while the normal 

 fibers remained unstained or only with light-colored yellow due to the 

 bichromate in the Miiller's fluid. 



SPINAL, CORD 



The spinal cord contributed the bulk of material for the study of 

 nerve changes. A number of pieces were taken from the cervical, 

 thoracic, lumbar, and sacral regions. These pieces were fixed by methods 

 best adapted for each particular stain. Fewer pieces were taken from 

 the dorsal region than from the cervical or lumbar, as was indicated by 

 the clinical symptoms and borne out by the microscopic examination. 

 The sections from the anterior and middle dorsal region when stained 

 with the Van Gieson method showed good contrast between gray and 

 white substances, unaltered motor-ganglian cells, and no increase or re- 

 duction in neuroglia tissue or in the size of the medullated nerve fibers 

 which constitute the dorsal, lateral, and ventral columns. The use of 

 Nissel's method showed the chromatophil granules well stained, unal- 

 tered in amount, and with no indication of any degenerative changes. 

 Pal's modification of the Weigert and the Marchi methods failed to show 

 any evidence of alteration in the myelin in the medullated nerve fibers. 

 The blood vessels appeared normal. Sections from the cervical and pos- 

 terior dorsal regions will be discussed at the same time, since they 

 showed similar lesions. 



In sections from these regions stained with the Van Gieson method 

 no appreciable changes could be observed either in the multipolar nerve 

 cells or in the medullated nerve fibers of the gray or white substance. 

 The Nissel method showed the chromatophil granules fairly well stained, 

 slightly disarranged, but not enough to produce a significant deviation. 

 Pal's modification of the Weigert method did not show sufficient differ- 

 ence in the medullated fibers to attach much importance to the lack of 

 contrast between the gray and white substances. In sections stained 

 by the Marchi method some of the medullated fibers in the dorsal horns 

 showed a few scattered black clumps, especially in the extramedullary 

 fibers outside the gray substance near the dorso-lateral groove. This 

 was the first indication of degeneration of the myelin. It could not be 

 detected by the other methods of staining. The medullated fibers of 

 the ventral horns showed no black clumps. There were no black clumps 

 in the medullated fibers of the dorsal columns in the white substance 



