THE SLEEPING SICKNESSES 



1267 



flattened. On careful examination, the pia arachnoid will be found 

 to be thickened in places, and may or may not be adherent to the 

 grey matter. The brain substance, which is generally firmer than 

 normal, but may be soft and oedematous, is usually congested, and 

 the fluid in the ventricles is increased. 



With regard to the spinal cord, it will be seen that there is an 

 increase of fluid, which, if examined with the microscope after 

 centrifugalization, generally shows leucocytes and trypanosomes. 

 The Cauda equina may be found at times surrounded by gelatinous 

 tissue. The cord itself is often congested, and haemorrhages have 

 been described. 



The lymphatic glands of the submaxillary region, anterior and 

 posterior triangles, around the bronchi, of the mesentery, behind 

 the peritoneum, as well as those of the inguinal and femoral regions, 

 may one or all be enlarged, congested, and even haemorrhagic. At 

 times abscesses are found in these glands, but they are due to 

 secondary infection. The abdominal cavity often contains some 

 straw-coloured fluid, and the pericardial fluid may also be ex- 

 cessive. There may be some increase in size of the lymph-follicles 

 and Peyer's patches of the small intestine. The lungs may show 

 signs of pneumonia and other complications. The other organs are 

 usually not markedly affected. 



The microscopical examination of the organs has been performed 

 with the greatest care by Mott and Breinl and the members of the 

 Portuguese Commission (Bettencourt, Kopke, Rezeide, and Maude). 



The utmost care must be taken to distinguish between the lesions 

 due to the tr^^panosomes and those caused by terminal infections 

 such as the diplococci, streptococci, and colon bacilli; for these infec- 

 tions may give rise to chromatolysis in the nerve cells and degenera- 

 tion in the nerve fibres of the brain (pons and medulla) and spinal 

 cord (especially in the posterior and lateral columns), and perhaps 

 in the peripheral nerves, which have nothing to do with the disease 

 in question. With this proviso the microscopical examination is 

 characterized by a round-celled infiltration surrounding the vessels 

 of the pia arachnoid of the brain and spinal cord. This infiltration, 

 first described by Mott, is best seen in the membranes, where there is 

 an accumulation of cerebro-spinal fluid, and in the brain, around 

 the vessels of the medulla, pons, cerebellum, and those entering the 

 base. The process appears to begin with a growth in size, and then 

 a proliferation of the neuroglia elements, which has been minutely 

 described by Eisath, and is found, not merely around vessels, which 

 show a small-celled infiltration, but around those which do not. 

 Round cells are found later in tlie meshes of this proliferated glia. 



These cells are (a) lymphocytes; (b) peculiar cells called the 

 ' plasma cells of Marschalko,' characterized by the nucleus becoming 

 situated at one end of the cell, and staining blue with methylene 

 blue and eosine, while a clear halo separates it from the cytoplasm, 

 which stains pink; (c) ' morula cehs of Mott,' which are large round 

 or oval cells with an excentric blue nucleus and a cytoplasm contain- 



