116 METHODS OF MICROSCOPICAL RESEARCH. 



been allowed for saturation therewith, the chloro- 

 form and the specimens are together heated to the 

 melting point of the paraffin, small pieces of paraffin 

 being gradually added during the heating ; air 

 bubbles will arise from the specimens, and when 

 these cease no further addition of paraffin will be 

 necessary. The " mass " must be kept at its 

 melting-point in a dry oven for some considerable 

 time after the addition of the paraffin, in order to 

 ensure the entire evaporation of the chloroform, 

 any remains of which in the mass would prevent 

 its becoming sufficiently hard to cut satisfactorily. 

 The embedding is of course done as in the ordinary 

 paraffin process. 



EMBEDDING IN GUM AND GLYCERINE. 



Iy Gum Acacise Mucilage, B.P., 90 parts. 

 Price's Glycerine 10 ,, 



Add 1 per cent, of carbolic acid crystals. 



Place the specimens to be embedded in this mix- 

 ture in watch glasses, or small (water colour) saucers, 

 and let them remain exposed to the air of the labo- 

 ratory for four days. In that time the mixture will 

 have set into a firm, gelatinous mass. Blocks, in 

 each of which one specimen is enclosed, are then to 

 be cut out, and again left exposed for three days to 

 hardeo, being turned over from time to time that 

 they may dry equally on all sides. When dry, the 

 blocks may be pared down to suitable size, and 

 affixed to corks with strong gum water, and on 

 these they may be preserved, to be sectionised as 

 required. 



The gum can be removed from the sections by 

 immersion in distilled water before staining them. 



