180 THE MICROSCOPE. Dec. 



on a slide and add a drop or two of alcohol. Let it re- 

 main until clear, then rinse in water, stain in ammonia 

 carmine or iodine green. Then remove from the staining 

 fluid, rinse in water, pass through weak, strong and ab- 

 solute alcohol, then place in oil of cloves for a few mo- 

 ments and transfer to a slide. From the end of a wire 

 drop sufficient xylol balsam to cover the specimen and 

 allow it to settle of itself; then put on the cover, being 

 careful not to entrap air bubbles. 



The vegetable sections prepared by W. White may be 

 used to advantage when fresh specimens are not avail- 

 able. These are already stained and mounted between 

 gelatine films. They can be soaked in turpentiniB until 

 clear and mounted in balsam as above. 



Ou a New Method of Entrapping, Killing, Embedding and 



Orienting Infusoria and Other Very Small 



Objects for the Microtome^ 



Bv John A. Ryder. 

 [Abstract of an article in the American Naturalist.] 



A reliable method of capturing, killing, staining and 

 dehydrating minute organisms has long been a desidera- 

 tum with biologists, especially when such objects fall 

 far below 1-lOOth of an inch in diameter. After trying 

 a number of devices, I hit upon a plan that is not only 

 ve^^ simple, but also capable of wide application, for by 

 its means organisms as small as l-200()th inch in diameter 

 may be caught and held. 



The filter upon which the objects are caught consists of 

 thin slices of elder pith. Get good, clean, whole pieces of 

 elder pith, and clamp a piece into the holder of a Schanze 

 or other sledge microtome, so as to make transverse sec- 

 tions of it, taking four to six divisions of the microtome 

 wheel to each section. The knife should be set at an 

 acute angle with the line of movement of the knife car- 



