184 Modern Microscopy 



embed in carrot, place in microtome, and cut sections as 

 thin as possible with a knife wetted with a little olive-oil. 

 As the sections are cut, put them on a slide, and place 

 out of reach of dust until you are ready to mount 

 them. 



Make a shallow cell as directed with black enamel and 

 let it dry, then proceed as directed for acetate of copper 

 mounting, but use castor-oil instead of copper solution. 

 When the cover has become fixed, wash away the exuded 

 oil with a soft brush and some turpentine, and, when dry, 

 apply a good finishing coat of black enamel. Water and 

 spirit are apt to injure the aleurone grains, so they should 

 be avoided. 



Marine Algae. The best place for collecting specimens 

 is a rocky shore, and the most suitable time is when the 

 tide is at its lowest. As a rule, the inshore weeds near 

 high-water mark are green, lower down there is usually a 

 belt of olive forms sheltering red plants beneath them, and 

 where rocks overhang small shallow pools red forms also 

 occur at this level. At extreme low- water mark and beyond 

 it are found brown tangles sheltering red plants again, 

 while at the lowest depths the red weeds occur without 

 shelter. The specimens will be found by searching the 

 rocks and pools, some will be growing on pebbles and on 

 shells, others will be attached to rocks, and varieties may 

 be found stranded on the shore thrown there by waves, 

 particularly after a storm, the tufts having been torn away 

 and carried inshore from inaccessible regions. 



For collecting, small tin boxes or an ordinary sponge bag 

 will be found most suitable. A strong chisel mounted on 

 a stout stick will also be required for removing specimens 

 from rocks that are out of reach. 



Many specimens may be preserved in sea water for a 

 considerable time, but, as a rule, the sooner they are 

 mounted the better. 



Mounting Process. Kemove the specimen from sea 

 water and wash well in fresh water. Place in a shallow 



