1897] MICROSCOPICAL JOURNAL 291 



of formalin with alcohol were also tried, and that which 

 seemed to be most completely satisfactory for quick pen- 

 etration and convenience, bacteriologically and histo- 

 logically, was as follows : 



95 per cent alcohol 100 parts. 



Commercial formalin (40 per cent formic aldehyde). 10 parts. 



Pieces of tissue, J centimeter square, are well fixed in 

 from twelve to twenty-four hours, after which it is well 

 to leave for a few hours in 95 per cent alcohol before 

 clarifying for the paraffin bath. Specimens, transferred 

 directly from the fixing mixture, have been clarified in 

 chloroform or cedar oil, but it requires a longer time. 



The addition of the formalin is advantageous, because 

 in a way it brings about a state of equilibrium. The 

 alcohol alone shrinks the tissue while on the other hand 

 formalin swells it, so that in this respect the one reacts 

 against the other. 



ADHESION TO THE SLIDE. 



After the infiltration and imbedding of the tissue in 

 paraffin, the question of the treatment of the sections is 

 one of some importance. If they are to be carried 

 through a series of reagents in watch glasses, and not 

 placed upon the slide until they are mounted, the sec- 

 tions must necessarily be rather thick, in order to with 

 stand the manipulation. Very much thinner sections, if 

 adherent to the slide, and consequently supported by it, 

 can be carried through the difl"erent steps of the process 

 without injury, and show the structural elements to much 

 better advantage. 



The albumen or collodion adhesive, usually employed 

 for this purpose, however, possesses the disadvantage of 

 taking the aniline colors used in bacteriology; sufficiently 

 to disfigure the preparations. If a clean slide be coated 

 with a thin film of glycerine and then rubbed very nearly 

 dry with a^loth or the hand, and a drop or two of 35 per 



