10 The Microscope. 



A few drops of the urine containing the sediment are taken up 

 in a i3ii3ette and a drop deposited on the center of a slide, a thin 

 cover-glass placed over it and the superfluous urine absorbed with 

 a piece of blotting paper. The top, middle and lower part of the 

 sediment should be successively examined to bring under obseiwa- 

 tion the constituents having different specific o-ravities. 



A cupped slide may be useful in searching a scanty deposit, 

 but the examination is hindered by the depth of the fluid and the 

 constant focusing of the microscope which is necessary. I find it 

 more convenient to examine a number of specimens on a flat slide. 

 A drop of a nuclear staining fluid, as ammonio-carmine,. added to 

 the drop of urine greatly facilitates the examination and well repays 

 one for the httle extra trouble. Casts, epithelial cells, organic 

 debris, etc., take the stain and contrast well with the unstained 

 crystals. For the detection of delicate hyaline casts this staining is 

 of great value. 



For the examination a good i in. objective, with a B eye-piece, 

 answers the purpose fairly well, but for the resolution of fine crystals 

 and delicate organic structures a moderately good | in. or 4- in. 

 objective is to be preferred. 



A little procedure that will be found very useful, particularly 

 for the study of casts, is to place the tips of the two index fingers 

 gently on the cover glass, and, with the object in view, to move the 

 glass slightly to and fro. By this movement a suspected cast or a 

 crystal may be rolled over and examined on all sides. The cylindri- 

 cal shape of many delicate casts can be shown only by this method. 

 It is delightful to note how this little manipulation enables one to 

 detei-mine the character of a doubtful object. 



Various extraneous matters, as pai'ticles of dirt, fibers of cotton, 

 wool, silk, etc., find their way into the urine, and the inexperienced 

 student is always first attracted and puzzled by them. A little study 

 soon gives such familiarity with them that they are passed over 

 without a thought. 



MICEOMETRIC MEASUREMENTS. 



M. D. EWELL, F. K. M. 8. 



T AST winter in order to test the relative accuracy of micrometrio 

 ^-^ measiu-ements with different apparatus in the hands of differ- 

 ent competent observers, I ruled on a glass slide 15 spaces of ap- 

 proximately .004 and .008 inch, without applying any corrections for 



