184 THE MICROSCOPE. Bee. 



may be little fresh water oysters, quartz, agate, sand or any ob- 

 ject that polarizes and does not dissolve in turpentine. The 

 objects are kept in motion by reversing the slide. Such slides 

 are novel and entertaining and nearly always excite the wonder 

 and admiration of friends. 



Ceratium. — This animal is a flagellate infusorian. It is in 

 the form of a hard shell with a long sharp peduncle and three 

 horns or processes at the top. The animal lives encased in the 

 shell and communicates with the outer world only b}^ means 

 of its flagellum. It is pictured in Dallinger's Carpenter, 7th 

 edition, on page 696. Also in the Century Dictionary, Vol. 1, 

 page 894. At certain seasons, it is found in great numbers in 

 the filterings of water of the Great Lakes. The most interesting 

 feature of the animal is its flagellum. This is easil}^ seen by 

 an ordinary quarter-inch objective. To observe it requires no 

 staining or manipulation. 



If a quarter-inch objective fails to reveal the flagellum, it is 

 because it has been drawn in b}' the infusoriaa. The animal 

 seems to be timid and the least disturbance will cause it to re- 

 tract its delicate flagellum. It is best to examine the Ceratium 

 when first gathered as it seems to be very delicate and easil}^ 

 killed. 



Opaque Slides with Asphalt. — Place an ordinary glass 

 slip on a turn table and turn a ring of asphalt and fill the in- 

 terior of the ring with the same substance. Rembv-e from the 

 turn table and burn the asphalt side of the slide over a a alcohol 

 lamp. After turning, immediately apply another coat of as- 

 phalt and burn again as before. While hot, place a cover glass 

 within the ring and trim the edges with turpentine. 



Cells made of a Button. — Procure a rubber button with a 

 *rim ; drill out the interior containing the holes and leave a 

 flange for the cover glass to rest upon. The edge of this flange 

 will protect the cover. Buttons may be obtained that will ex- 

 actly fit a 5-8th cover. Fasten the ring to the slip with bal- 

 sam or with any kind of cement. If the circle be too large for 

 the cover fill it with a drop of asphalt. Very beautiful cells 

 can thus be obtained. 



