10 



Hyaline fibrin thrombi in the glomerular capillaries and in other 

 renal vessels were found in cases Xos. 2, 11, 13, 14, 15, 16, 17, 18, 

 20, 23, 30, 31— that is, in 12 out of 31 cases, or in 38.71 per cent 

 of the material investigated. These 12 cases are distributed among 

 the six pathologic groups as follows : 



Total Renal 

 Group. I number fibrin 



Pereent- 

 of cases, thrombi. *^*'' 



I. Primary uncomplicated bubonic plague 



II. Primary bubonic plague with secondary plague 

 septico-pyemia 



III. Primary bubonic plague with secondary plague pneu- 



monia 



IV. Primary uncomplicated plague pneumonia 



V. Primary pneumonia with secondary septico-pyemia 



VI. Primary plague septicemia " " 



Total 



Average per cent ! 38. 71 



The methods used in the histologic examination of our material 

 were as follows : 



Pieces of tissue from the plague bubo and from the internal 

 organs in each case were immediately fixed in Zenker's solution 

 during the autopsy. In a few cases other fixing fluids were 

 used as a control, viz, Muellers fluid, the Mueller-Orth formalin 

 mixture, and others. Subsequently, the material was dehydrated 

 in alcohol and embedded in paraffin. The sections were stained 

 with hematoxylin-eosin, eosin-alkaline methylene blue, according to 

 Weigert's fibrin method (preliminary carmin stain), Mallory's 

 anilin-blue for connective tissue fibers, dilute carbol-fuchsin, and 

 Wright's modification of Eomanowski's stain. The best method in 

 the study of the thrombotic processes in plague is furnished by 

 Weigert's fibrin stain after fixation in Zenker's solution. Fixation 

 in riemming's solution or in Mueller's or Mueller-Orth's fluid is 

 absolutely inadmissible for the study of the thrombotic processes. 

 According to Disse the methods to be recommended in the fixation 

 of renal tissues are very limited. Chromic acid and its salts, alco- 

 hol, and many other means frequently employed are inadmissible; 

 but Zenker's solution, which acts like saturated corrosive sublimate, 

 is to be recommended. 



In all of the cases in which we found hyaline thrombi in the 

 kidneys, sections were also stained by Van Gieson's method. The 

 hyaline thrombotic material always stains yellow, never pink or 



