1684 



BERI-BERI AND EPIDEMIC DROPSY 



the microscope shows nothing abnormal except in the bulb, where, 

 according to Wright, there are the changes already mentioned in 

 the vagal nucleus. Kustermann also describes acute degeneration 

 of the vagal ganglia at the base of the fourth ventricle. 



The spinal cord is usually normal. Hamilton Wright and others 

 have described degeneration of the cells of the posterior spinal 

 ganglia and anterior cornua of the lumbar cord, together with 

 atrophy of Goll's column, in which histologically there is a thicken- 

 ing of the glia tissue and a complete disappearance of the nerve 

 fibres, with the presence of many granular cells. 



The peripheral nerves are usually normal to the naked eye, but 

 may bfc injected and hsemorrhagic. Scheube and Baelz first showed 

 that these nerves were degenerated, the muscular branches of the 

 nerves of the limbs being most affected, but even the fine sensory 

 cutaneous branches were also attacked. The changes in the auto- 

 nomic nervous system do not appear to have been closely studied, 

 though several observers have recorded changes in the ganglia, and 

 in the cardiac and other plexuses. 



The degeneration of the nerve fibres has been carefully studied 

 by Scheube, Baelz, Hamilton Wright, and Duerck. The neuro- 

 keratin network becomes irregular, and its meshes wider, while its 

 rods disappear. The medullary sheath becomes vacuolated, and 

 its inner boundary ill-defined. In other places the neurokeratin 

 network condenses into small rosary-hke masses or larger lumps, 

 somewhat regularly arranged. Later the medullary sheath breaks 

 up into spherical or elongated masses separated by clear intervals. 

 The axone undergoes first chemical changes, and then appears like 

 a wavy cord, or as a series of comma-like segments, or twisted up 

 into a coil. Finally, both axone and medullary sheath disappear, 

 while Schwann's sheath collapses, and so the nerve fibres become 

 lost in the connective tissue of the endoneurium. Along with these 

 changes there is a cellular infiltration of the perineurium, especially 

 of the perivascular spaces, and also of the endoneurium. These 

 cells are said to be like a similar infiltration met with in traumatic 

 lesions of nerves, and to resemble the granule cells of the central 

 nervous system. When fully degenerated, the nerve may consist 

 simply of connective tissue. Regeneration has not been observed, 

 but must occur — at all events, to some extent — in cases which 

 recover. 



The muscles show atrophied and normal fibres side by side. The 

 diseased fibre first loses its striation, and becomes oval or round in 

 transverse section. A colloid degeneration occurs, with prolifera- 

 tion of the nuclei of the sarcolemma. The fibre now appears of a 

 homogeneous grey colour, and is very brittle. As it atrophies the 

 connective tissue of the muscle increases in amount. The bone- 

 marrow is said to be normal. 



Symptomatology. — As the cause of the disease is unknown, and 

 the invasion is insidious, the incubation period is also unknown. 

 Hamilton Wright places it at some ten to fifteen days. 



