1885.] Microscopy. 735 
It consists of a copper rod, A, two inches or more in diameter 
and six inches high, inclosed by an inner zinc (6) and an outer 
brass tank (c). Above is the table, D, working on a fine screw 
Through the center of the table passes a narrower portion 
of the copper rod, the piston (). 
When the inner tank is filled with a mixture of salt, ice and 
water, the temperature of the copper rod is so reduced as to 
an en amma 
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Fic. 1.—Freezing microtome. 
freeze any object (F) placed on its upper end. The size of the 
rod is such that its temperature will remain very steady for from 
four to six hours without any further care on the part of the 
erator. : 
pee this arrangement, the advantages of which will be readily 
seen, objects can be easily frozen, and without any slop or 
(£3 m ” 
The imbedding medium is composed of: 
Gum arabic . 5 
Gum tragacanth I 
I 
Gelatine 
