86 GENATINOUS, CRUSTACEOUS, AND STONE-LIKE ALGiE. 
in order to remove the last trace of lime. After waiting a 
short time, the sections may be removed with a soft brush 
into a saucer, and the acid washed out of them. This last 
circumstance should be carefully attended to, as the gases 
released from the acid are apt to attack the lenses and do 
them serious injury. The object is now ready for exami- 
nation under the microscope, for which purpose it has 
simply to be laid on a slide under a thin covering glass. 
A gentle pressure given to the latter will cause the fila- 
ments to recede from one another, and ensure the trans- 
parency of the preparation. 
