324 NATURAL HISTORY OF OUR SHORES 



cutting as does the wax process. Still, with a small 

 object, the sections may be cut to the five -hundredth 

 of an inch. 



Dissolve chips of celloidin in equal parts of absolute 

 alcohol and ether to the consistency of ordinary syrup. 

 A stock of this can be made, and kept in a well-stoppered 

 bottle. 



(Ordinary collodion, as sold at the druggist's, will do 

 instead of this ; but it must not be the " Elastic Collodion," 

 which contains an oil.) 



The object to be embedded is best stained " en bloc." This 

 saves a lot of work, only it must be remembered that some 

 things are not readily permeable to the stain; but the 

 majority of things can be so stained. For staining, cut the 

 object to the size that the area of the sections are to be, 

 and give it a prolonged soaking in weak stain. It must have 

 the appearance of being much too dark, as the colour is 

 deceptive when seen in the lump. 



The object, being properly stained and washed, must be 

 placed for a while in medium strength spirit, then in 

 stronger, then in absolute alcohol until " dehydrated." It 

 must now have a few hours in equal parts of alcohol and 

 ether, after which it is put in the celloidin mixture, in a 

 wide-mouthed, stoppered bottle. Here it may remain, no 

 matter how long, but must have, at least, time for the 

 celloidin to penetrate it all through. This depends upon 

 the nature of the object and its size, but as a rule two or 

 three days will do. It must then be transferred to a stiff er 

 celloidin solution, or the stopper of the bottle may be left 

 out until the solution is very viscid and " stringy " when 

 the object is lifted. Now take out the object, and drain 

 it of the excess of celloidin, just allowing a film to adhere 

 to its surface. Now place it in methylated spirit, or still 

 better, in chloroform, and the celloidin will harden, and 

 become transparent. In a day or two it will be firm, 



