12 THE MICROSCOPE. Jan. 
PRACTICAL SiGe s ii Nes. 
BY ly. A. WILLSON, 
CLEVELAND, OHIO. 
Any Easy Method of Seeing the Minute Structure of 
Fossil Wood.—Receiving a smalllump of fossil wood from 
a sub-carboniferous deposit, wrapped in paper, I noticed a 
small amount of dust fallen from the fossil into the paper. 
Placing a small amount of this dust upon a slide in a drop 
of water, covering and filling the space beneath the cover 
with water, I was rewarded by the sight of round cells 
each of which contained a well defined passion cross. It 
was a beautiful and instructive sight. Some of the pieces 
were dark and opaque but the portions exhibiting the cells 
were of a light brown color and thin enough for examina- 
tion under a high power. ‘The specimen seemed to be a 
mixture of carbonaceous and siliceous rock of a denser 
structure than coal. 
Another specimen was white and composed almost en- 
tirely of silex. Quite large specimens of the latter flaked 
off and were thin enough for examination under a fifth or 
a quarter objective. They mounted well in balsam and 
exhibited the bordered pits of the coniferae. The dust in 
the first specimen could be easily obtained by scraping. - 
Trachea.— The Trachea or air tubes of insects are in- 
teresting and beautiful objects. They are more easily ob- 
tained from the larve. To obtain them, make a small 
opening in the body and then inject into the opening strong 
acetic acid, this will soften and decompose all the viscera, 
and the trachea should then be well washed with a syringe 
and removed from the body. This latter process may be 
easily effected by cutting away the connections of the main 
tubes with the spiracles by means of fine pointed scissors. 
Then place the body upon a glass slp, flood with water 
when the trachea will float out. Then lay them out and 
place them in their proper positions with needles; dry 
well, soak in turpentine and mount in balsam. ‘The best 
