TOOLS AND METHODS OF WORK 27 



3. Place the specimens in chloroform; allow to stand twelve hours. 



4. Place the specimens in a saturated solution oi paraffin in chloro- 



form; allow to stand twelve to twenty-four hours or longer 

 according to size of specimen. Melting point of the paraffin 

 should be about 130 degs. Fahr. 



5. Transfer the specimens to paraffin (free from chloroform) melted 



in the water-oven — the heat must not be higher than one 

 degree above the melting point of the paraffin; allow the 

 specimens to remain in the water-oven for two or three hours, 

 change the paraffin at intervals. By this means the chloroform 

 is evaporated, or thrown off, and the tissues become infiltrated 

 with pure paraffin. It would perhaps be preferable to use 

 several tubes containing melted paraffin and transfer the 



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Fig. 17. — Moulding frame, formed of two L-shaped pieces of brass, with arms 

 one and a half inches long and half-inch angles. 



specimens from one to the other, allowing them to stand a 

 short time in each, care being taken that the heat is only 

 just sufficient to keep the paraffin in a fluid condition. 



6. Have ready a quantity of freshly-melted paraffin, pour this into 

 the mould (Fig. 17), place in the specimen, and arrange it in 



