METHODS OF ELICITATION OF PHENOMENON 207 



varying degrees. The thrombi which consisted of amorphous eosin- 

 ophilic masses filled the glomerular capillaries almost completely. 

 W^ith W^eigert's fibrin stain they appeared deep blue, biu no fibrin 

 strands were discernible. The larger renal vessels, in these in- 

 stances, Avere unaltered. 



Focal cortical necrosis appeared grossly as scattered, irregtdar, 

 gray-red smlace Hecks, accompanied frecjuently by ])in-head size 

 hemorrhages. Microscopically, there Avere focal areas of tid^idar 

 necrosis sharply defhied from the smrounding intact tissue. Most 

 commonly, the convoluted tid)ules were involved. In a ntnnber of 

 instances, tidjidar necrosis occiured alone, ^vithout any other 

 alterations. Howe\er, this lesion ^vas foiuid more commonly in 

 association ^vith hemorrhages and Avith foci of glomerular capil- 

 lary thrombosis and glomertdar hemorrhage (Fig. i^a) . In the 

 latter instance, it ^vas possible to demonstrate the presence of 

 necrosis and thrombosis of branches of the interlobidar arteries 

 corresponding to the focal necrotic areas. Serial sections demon- 

 strated that only a short segment of the vessel ^vas involved. 

 The entire wall ^vas necrotic, ^vith extravasation of erythrocytes 

 and filling of the liunen by a thrombtis that contained chimps of 

 fibrin. Polymorphonuclear leucocytic infiltrations ^vere seen 

 about the necrotic portion of the vessel. At times the necrosis 

 extended into the afferent arterioles of the gl(Mueruli. 



The most striking renal lesion observed in the gross ^vas that of 

 diffuse cortical necrosis. The sinface ^vas irregidar and covered by 

 ninuerous ele\ated, hemorrhagic areas alternating ^vith depressed 

 gray areas. The process ended abruptly at the medidla. Histologi- 

 cally, these kidneys sho^ved diffuse tubidar necrosis, interstitial 

 and glomerular hemorrhages and glomeridar ca})illary throm- 

 bosis. Many glomeruli ^vere replaced by hemorrhages ^vhich filled 

 the entire capsidar space and did not permit the recognition of 

 the capillary loops (Fig. 17B) . The tubides showed various stages 

 of necrosis. There was necrosis of the interlobidar arteries, as 

 described above, ^vith hemorrhage around and into the "vvall of 

 the vessels and perivascular leucocytic infiltration. Only small 

 residual areas of uninvolved renal tissue ^vere found. These ^vere 

 demarcated from the necrotic areas by a dense zone of leuco- 

 cytic infiltration. Not infrequently, glomeruli in these uninvolved 

 zones showed focal glomerular capillary thrombi and extravasa- 

 tion of erythrocytes into the capsular spaces. 



With the elastica stain the necrotic vessels shoAved complete 



