134 BACTERIOLOGICAL ANALYSIS LESSON 



(5) Transfer the specimens to liquid hard paraffin (56 

 to 60 C.), and allow them to soak for five minutes. 



(6) Pour the paraffin and the tissues into a small paper 

 box, and when the paraffin is set, cut out the pieces of 

 tissue, fix them on the rocking microtome, and cut a 

 number of sections, which must be received in warm water 

 at 60 to 65 C. 



(7) Fix the sections on cover-glasses and dissolve off the 

 paraffin in the usual manner (vide p. 64). 



(8) Now stain the specimens fixed on the cover-glasses : 



(a) according to Gram's method, as described on pp. 

 70 and 71 ; 



(b) with methylene-blue for five minutes ; wash in 

 water for half a minute, then in water acidulated 

 with acetic acid for half a minute, and again in 

 water for half a minute ; dehydrate in alcohol, 

 clear and mount (vide p. 35). 



Examine the sections under the microscope. 



In this manner good specimens can be obtained in less 

 than three hours. 



Slow Method of Hardening Tissues 



(1) Pieces of tissues from the mouse also should be 

 placed for a few weeks in Miiller's fluid, which must be 

 changed from time to time. 



(2) Then wash the specimens in running water, to 

 remove the Miiller's fluid. 



