140 



Modern Microscopy 



Freezing Microtome. Cathcart's is the most simple 

 and cheapest freezing microtome, and it can be obtained 

 from any optician. 



(1) Cut a slice of the specimen about |--inch thick, in the 

 direction you wish to make the section. 



(2) Place in water for an hour to remove the alcohol. 



(3) Transfer to a mixture of gum- water 5 parts, saturated 



FIG. 53. CATHCART'S MICROTOME. 



watery solution of loaf-sugar 3 parts, and allow it to soak 

 in this for about twelve hours ; or, if a few drops of carbolic 

 acid are added to the mixture, tissues may remain in it for 

 months without harm. 



(4) Clamp the microtome to a table, fix the ether spray 

 in its place, and fill the bottle with ether. Methylated 

 ether, sp. gravity 720, will do. 



(5) Put a little gum-water not gum and syrup on the 



