30 PRACTICAL BACTERIOLOGY 



3. During the process of fixing, the specimen must on no account 

 be scorched in the flame, otherwise the form and staining properties 

 of the bacteria, etc., are entirely lost. 



4. To remove immersion oil from the cover-glass of a freshly 

 mounted specimen absorb the most of the oil with a piece of filter 

 paper, then the remainder can be removed with xylol when the balsam 

 sets. 



XXXI. METHODS OF EXAMINING SECTIONS OF 

 ORGANS AND TISSUES FOR THE DETECTION 

 OF BACTERIA. 



There is no method of demonstrating bacteria in unprepared 

 specimens. All tissues, organs, etc., must be cut into sections to 

 study the relative position of the bacteria present in the tissue; 

 and before cutting into sections, the tissue, organs, etc., must be 

 thoroughly fixed and placed beyond the reach of cadaveric changes 

 as follows : 



1. Cut the portion of organ or tissue into pieces the size of a nut 



before putrefactive changes can take place. 



2. Place the squares of tissue on small pieces of filter paper, 



write the name of the organ or tissue on the side of the 

 paper, and place in alcohol, when the block of tissue 

 becomes firmly fixed to the filter paper, which also assists 

 in keeping the portion to be hardened above in the 

 anhydrous stratum. 



3. The blocks of tissue remain two or three days to harden in 



the alcohol, which is changed several times. 



4. Pieces of kidney, liver, and muscle, after remaining in alcohol 



two or three days, can be fastened to a block with the 

 following preparation : 



Gelatine . . 1 gramme. 

 Water . . 2 c. c. 

 Glycerine . 4 c. c. 



Heat and dissolve to a thick consistency, when the tissue 

 is fastened to the block with the above adhesive mixture, 

 place in alcohol, preparation side downwards, and in 

 twenty-four hours the gelatine fixing will be sufficiently 

 hard to admit of the tissue or organ being cut into 

 sections with the microtome. 



