The Microscope. 127 



4. In examining urinary casts, gentle pressure on the cover- 

 glass by means of the finger or teasing needle, will cause the cast to 

 roll so that all sides may be seen. 



4. We have never been troubled by mucus in the way de- 

 scribed. A little mucus is sometimes desirable as casts, crystals, 

 etc., become entangled in the threads and may then be readily 

 detected. You use too coarse a pipette. Try Squibb's minim 

 nipple pipette. 



6. We have used equal parts of glycerine and camphor water 

 for preserving urinary sediments. Another preservative, recom- 

 mended by Prof. Woods, of Harvard Medical School, which is 

 excellent, consists of acetate of potassium with a little carbolic acid. 

 It is desirable that the acetate have a Sp. gr. between 1,050 and 

 1,060, and should contain carbolic acid in proportion of 4 or 5 cc. of 

 the deliquesced acid to the liter of solution. 



Casts may be stained with eosin. Wash the sediment with 

 distilled water, then cover for half an hour or longer with eosin in 

 proportion of 5 grains to the ounce of water-alcohol (3 to 1 ). 

 Wash again, and place a drop of the stained sediment on a slide. 

 Dry ; wash with alcohol, clear with turpentine or other agent, 

 mount in balsam. Or, mount in the glycerine-camphor, Tarrant's 

 solution, or Wood's preservative. In this instance the cover-glass 

 must be sealed. 



7. The eye-piece mentioned can be used, but it is bad practice 

 to increase magnification in this way. Use a higher power 

 objective. 



8. The dropper in the cork bottle for stains has long been 

 in use. 



9. The word micron was introduced by Listing in 1869 as the 

 name of the unit of measure in micrometry, viz. : 1 . 1000 of a mili- 

 meter. The Greek letter p. is used to designate micron. 



10. The number of glomeruli in the human kidney has not 

 been computed. 



11. If physicians are, as a rule, poor microscopists, it is cer- 

 tainly their privilege, as well as duty, to support such a journal as 

 The Microscope, which deals with every aspect of this great subject. 

 We are always glad to answer all qiiestions of general interest, and 

 will give as much attention to such inquiries as space permits. 



5. K. J., Norfolk, Va. — Celloidin is a pure pyroxylin soluble in 

 equal parts of absolute alcohol and sulphuric ether. It comes in 

 chips and tablets, the former being preferable for microscopic use. 

 It may be obtained of Bachrach Bros., Baltimore, Md. 



