164 Modern Microscopy 



drain and dry, and then apply a drop or two of Canada 

 balsam on the cover-glass. 



Vermes. Sections of specimens such as Acaris, Taenia, 

 etc., may be made in the following way: Harden the 

 worm in alcohol for a week or ten days. Then cut up in 

 pieces of about J inch long, and soak in equal parts of 

 ether and alcohol for twelve hours ; they are then trans- 

 ferred to a thin solution of celloidin in equal parts of ether 

 and alcohol, and must remain in this until perfectly 

 infiltrated. Now remove from thin celloidin and place in 

 a thicker solution, and soak again for twelve hours. 

 Remove from celloidin on the point of a needle, and hold 

 exposed to the air for a, minute or two so that the celloidin 

 may dry all round the exterior of the specimen ; then push 

 it off the needle into methylated spirit, in which it should 

 remain for twelve hours to complete the hardening of 

 celloidin in the interior. Cut transverse sections, and stain 

 in borax carmine for five minutes. Wash in methylated spirit, 

 and then place in acidulated spirit 1 part hydrochloric 

 acid in 5 of methylated spirit for about three minutes if 

 over-stained, until the excess of stain is removed. Wash 

 again well in methylated spirit to remove all trace of acid. 

 Then transfer, for about one to two minutes, to absolute 

 alcohol, clear in oil of origanum, and mount in Canada 

 balsam. 



Great care must be taken not to leave the section in 

 absolute alcohol for more than two minutes, or the cel- 

 loidin will be dissolved and the section will fall to pieces. 



Heads and segments of tape-worms, flukes, etc., may all 

 be mounted whole. Harden in methylated spirit for a few 

 days, then stain in borax carmine for from one hour to 

 twenty-four hours according to the size of the specimen. 

 Wash in methylated spirit, and soak in acidulated spirit 

 until the excess of stain is removed. Then place in water 

 for a few minutes to soften the tissue a little. Place the 

 specimen on a glass slide, put another slide on it, and press 

 down carefully until quite flat. Now bind the two slides 



