126 THE MICROSCOPE. [May, 



28. Ani?jial a?id Vegetable Cell. Wkat is the difference 

 chemically^ 7nicroscopically ^ and morphologically ? — A. E. 

 I^arson. 



A cell is a vitalized mass of albumen called protoplasm. If its 

 vitality is sustained by the assimilation of other organized ina- 

 terial it is presumed to be animal ; if sustained by inorganic mat- 

 ter only it is probably vegetable. As animal cells are known to 

 require both organic and inorganic material, no characteristic dif- 

 ference or definition has yet been formulated. 



29. White Blood Corpuscles. How can I make permanent 

 stained cover-glass preparations? — E. L. 



Place a drop of blood on the cover and quickly sweep it oft' 

 with the straight edge of a glass slip, leaving only a thin, even 

 layer ; immediately place it in the fumes of an osmic acid solution ; 

 after an hour or two the blood corpuscles will be darkened some- 

 what, but no special details are made visible by this or any other 

 method of staining, therefore simply spreading and drying are 

 sufticient ; a glass slip having an old, well-hardened ring of shel- 

 lac is warmed enough to make the varnish sticky ; the well-dried 

 cover is placed on the soft ring and pressed down. In normal 

 blood one white corpuscle to about three hundred red ones may 

 be expected. In certain diseases, cancer, tuberculosis, and es- 

 pecially leucocythaemia, the white corpuscles are relatively more 

 numerous. The Microscope., Vol. XI, page 89, contains an arti- 

 cle on stainins: blood with eosin. 



30. Spermatozoa. Uoiu 7nay perma7ient mounts be m,ade to 

 show the organisms., stained or unstained ? — H. L. 



!;5taining spermatozoa with eosin or aniline dyes may be done, 

 but it adds nothing to details and is useless. Place a drop of the 

 spermatic fluid on a slip, press a cover down upon it, and let it 

 dry. A ring of varnish will prevent the intrusion of immersion 

 fluids. A mount prepared as above, but with no ring or other 

 protection, is now, after 6 years, apparently unchanged and shows 

 the spermatozoa perfectly. 



WAVS • 

 AND- MEANS 



Practical Points in Handling Objectives to Obtain 

 Best Definition. — If you want to compensate for thinner 

 cover-glass, set the systems of your objective further apart ; or 



