180 PATHOLOGY OF TYPHUS IN MAN 



In our series we found with regularity lesions of the xosette 

 and star types in the locations specified by Spielmeyer. The 

 "Strauchwerk" lesion was not present in typical form as illus- 

 trated by Spielmeyer in any of our human cases. In the 

 molecular layer of three cerebellums we found small areas of 

 diffuse neuroglia increase in each instance associated with 

 marked capillary dilatation in the same area. In the cerebel- 

 lums of guinea-pigs we have frequently found lesions simulat- 

 ing closely the illustrations of Spielmeyer 's "Strauchwerk" 

 lesions and here also we have demonstrated that the network 

 of neuroglia cells giving rise to this picture are apposed to very 

 fine capillaries. In guinea-pigs mitotic figures are not uncom- 

 mon in neuroglia cells lying in contact with the capillary walls. 

 We feel imposed to emphasize the delicacy of the capillaries 

 in the ganglion cell layers of the cerebral cortex and in the 

 molecular layer of the cerebellum and the possibility of failing to 

 identify capillaries even in thin sections when not injected with 

 red blood cells. The capillaries to which we refer have apparently 

 lumina permitting the passage of single red blood corpuscles 

 only. In the thick sections employed by all of the German in- 

 vestigators details involving capillaries might escape notice. 



The histology of the type lesion of typhus in the central 

 nervous system, the compact lesion of Spielmeyer, the nodular 

 lesion of others, was quite accurately described by von Pro- 

 wazek, who recognized that neuroglia cells were an important 

 constituent of the nodule. Polymorphonuclear leucocytes, rare 

 endothelial cells, plasma cells, and rod cells were all included 

 by him. Benda, Ceelen, Nicol, and Spielmeyer all emphasize 

 the role of the neuroglia cell in the formation of the nodule. 

 The presence of polymorphonuclear leucocytes, plasma cells, 

 and rod cells is described by each of the above authors. Spiel- 

 meyer states specifically that the amoeboid neuroglia plays 

 no part in the formation of the lesion. 



We have devoted much time to the study of these very in- 

 teresting lesions in the human brain and have controlled our 

 observations by a study of the brains of thirty guinea-pigs, 

 showing these lesions. The animal material proved particu- 



