PATHOLOGY OF HYDROPHOBIA 577 



latter, to make a smear which is then fixed in methyl alcohol for five 

 minutes and stained by Giemsa's stain (p. 115) for half an hour to three 

 hours ; the preparation is then washed in tap water for 2-3 min. and 

 dried. For rapid work, after fixation, equal parts of distilled water and 

 stain are used instead of the more dilute mixture. 



For sections the tissues are left in Zenker's fluid l for 3-4 hours, then 

 placed in tap water for five minutes, 80 per cent, alcohol with enough 

 i i ii line added to give it a port wine colour for 24 hours ; 95 per cent, 

 alcohol and iodine, 24 hours ; absolute alcohol, 4-6 hours ; cleared with 

 cedar oil and embedded in paraffin of melting point 52 C. ; sections should 

 1" "> to 6 /x thick. For staining, Mallory's methylene-blue eosin is 

 recommended ; the steps are as follows : xylol ; absolute alcohol ; 95 

 I >i r cent, alcohol and iodine, J hour ; 95 per cent, alcohol, ^ hour ; 

 a I isolate alcohol, hour ; eosin solution (5-10 per cent, aqueous solution), 

 20 minutes ; rinse in tap water ; Unna's polychrome methylene-blue 

 solution diluted 1-4 with distilled water, 15 minutes ; differentiation in 

 !5 per cent, alcohol for 1-5 minutes (the preparation being kept in 

 motion and its progress watched with a low power) ; rapid and careful 

 dehydration and clearing. 



Frothingham recommends a method of making "impression prepara- 

 tions " of the brain. The part (e.g. hippocampus) is laid on a piece of 

 wood whose porosity causes it to adhere ; a clean slide is then lowered 

 upon the tissue and slight pressure applied ; on raising the slide a 

 thin film of cells preserving their original arrangement is lifted off, 

 and this can be fixed and stained like a smear, van Gieson's method 

 being used by this author. 



The Xegri bodies (Plate IV., Fig. 16) 2 vary much in size, 

 m'Msuring from *5 to 25 //,. They are round, oval, or angular 

 in outline. They are found in the protoplasm of the nerve cells 

 and of their processes. When examined in unstained prepara- 

 tions, they are seen to have a sharply defined outline, and some 

 of the features of the internal structure presently to be described 

 can be noted. With regard to staining reactions, they are 

 ! rankly eosinophil for certain combinations containing eosin, 

 e.y. alcoholic eosin-methylene-blue, Mann's eosin mixture, and, in 

 certain circumstances, Leishman's stain. For the finer differen- 

 tiation of the internal structure, Negri employed Giemsa's stain. 

 With this stain and under high magnification the groundwork 

 of the body is a pale blue ; in it there appear certain round or 

 oval, multiple or single formations, of varying size, stained pink, 

 sometimes occupying nearly the whole of the body, sometimes 

 being relatively small (grosse Innenformationen). In addition, 



1 Zenker's fluid is of the following composition : potassium bichromate 

 J-f> .m-., sodium sulphate 1 gr., perchloride of mercury 5 gr., glacial acetic 

 a>-i'l 5 c.c., water to 100 c.c. Dissolve the perchloride of mercury and the 

 l.ulirouiate of potassium in the water with the aid of heat and add the 

 a.-rtir acid. 



- For the material from which this preparation was made we are indebted to 

 nipt. W. F. Harvey, I. M.S. 



37 



