220 DESCRIPTION OF PLATES 



FIGURE 66. Large paired rickettsia in endothelial cells in situ in an arteriole 

 of the skin cut longitudinally. Autopsy 1, death on tenth day. Com- 

 pare with the photomicrograph in Plate XXXII, figure 81. 1,800 

 diameters. 



FIGURE 67. Artery of the skin, a portion of the same vessel shown in 

 Plate XXVIII, figure 68. A swollen phagocytic endothelial cell in 

 situ is filled with the small forms of rickettsia. Autopsy 1, death on 

 tenth day. Compare with the photomicrograph in Plate XXXII, 

 figure 80. 1,800 diameters. 



PLATE XXVIII 



FIGURE 68. Large forms of rickettsia in an endothelial cell of an artery of 

 the skin. Other parts of the same section through this vessel show mural 

 thrombi and the endothelial cell illustrated in Plate XXVII, figure 67. 

 Autopsy 1, death on tenth day. 1,200 diameters. 



FIGURE 69. Early vascular lesion in cerebral cortex of guinea-pig 46 (see 

 protocol, page 105) inoculated with viscera of Louse 2, Box 38. A 

 precapillary with rickettsia in endothelial cells, scattered and in a clump 

 indicated by the arrow. Animal killed on third day of temperature. 

 Compare with photomicrograph, Plate XXXI, figure 78. 1,800 di- 

 ameters. 



PLATE XXIX 



FIGURE 70. Arteriole of skin, showing swollen degenerated endothelial 

 cells and an early fibrin mural thrombus. Two endothelial cells contain 

 rickettsia. There is an early perivascular reaction (endothelial leuco- 

 cytes). Autopsy 29, death on fourteenth day. 1,800 diameters. 



FIGURE 71. Precapillary arteriole of skin, showing paired large rickettsia 

 in the swollen endothelium. Autopsy 14, death on tenth day. Compare 

 with photomicrograph, Plate XXXII, figure 82. 1,200 diameters. 



FIGURE 72. Arteriole of skin, showing early typhus lesion, degeneration of 

 the endothelium and beginning mural thrombus. The swollen endothe- 

 lium contains many small rickettsia bodies. Autopsy 32, death on 

 fourteenth day. 1,200 diameters. 



FIGURE 73. Capillary of skin with five pairs of large rickettsia in the swollen 

 epithelium. A mast cell lies close to this capillary and is illustrated for 

 the comparison of mast cell granules and rickettsia. The former are 

 larger and stain more deeply and with a different coloration. Autopsy 3, 

 death on ninth day. 1,800 diameters. 



