1894 THE MICROSCOPE. 109 



The B. & L. Opt. Co. uses a tube length of 8? inches, their style 

 of eye piece projects I of an inch above the tube, making a total 

 length of9Hnches. The objective in both cases completing 

 the 10 inches. The short or continental tube may be measured 

 as above, 6 4-10 inches from eye lens to shoulder for objective. 

 This is the proper length for the usual French and German 

 objective. 



200. — Please cite publications upon our Amoeba, since Leidy^s 

 " Rhizopoda " was published. W. L. Poteat. 



See Am. Mo. Mic. Journal vol. X, pge 151 ; vol. XII, pge 

 153, vol. VIII, pge 234 for valuable information on Amoebas. 



PRACTICAL SUGGESTIONS. 



By L. A. WIIvLSON, 



CLEVELAND, OHIO. 



How to Examine Pollen. — To see the shape of pollen 

 grains the}" should be examined without a cover or in a cell as 

 the cover nearly always presses them out ot shape and imparts 

 an incorrect idea of their form. 



In the common yellow dock, (Rumex crispus), if viewed un- 

 der a cover, the grains appear round ; but, if viewed with an 

 inch objective, they are seen in their natural condition as cubes. 

 An inch objective and a D eye piece is preferable to a quarter 

 inch. The grains are best seen as opaque objects or by oblique 

 illuminations, with a spot lens or a parabaloid. 



Staining and Mounting Pollen. — A slide of assorted and 

 stained pollen grains is instructive and attractive. Place the 

 pollen in a small test tube and use any of the aniline dyes used 

 for staining eggs at Easter time. The pollen must be placed 

 into the staining solution while it is hot. It may then be dried 

 on the slide and mounted in balsam. For examining fresh 

 pollen or even for mounting pollen, castor oil is one of the 

 best media. This medium clears the grains beautifully and 

 shows their markings distinctly. The grains may also be 

 stained by aniline colors dissolved in alcohol. 



Paste Eels (Anguillulse aceti). — Paste eels and vinegar 

 eels have been determined to be of the same species but the 



