332 HOW TO SEE WITH THE MICROSCOPE. 



of baryta; this will gradually sink to the bottom of 

 the beaker; continue thus the addition until no further 

 precipitate can be detected by the eye. By waiting a 

 few moments the liquid above the precipitate will be- 

 come clear, when another drop or two of the standard 

 solution may be added. Should this cause a further 

 precipitate, continue in like manner to add the standard 

 solution; when no further precipitate forms, place a 

 few drops of the sulphate of soda solution in one of 

 the smallest test tubes, and to this add a drop or two 

 from the beaker; if a white precipitate appear in the 

 test tube, the standard solution has been added to the 

 beaker in excess ; and if the precipitate be very dense, 

 the analysis will have to be repeated, using greater 

 care towards the latter part. The number of grains 

 finally shown by the burette, divided by fifty, indicates 

 the number of grains of sulphuric acid to the fluid 

 ounce of urine. 



The final determination in this analysis as to the pre- 

 cipitation of all the sulphuric acid renders this tritation 

 somewhat more troublesome to the beginner than the 

 preceding. The practitioner should therefore, by re- 

 peated trials, become acquainted with the details. * In 

 examining the test tube as to the precipitate, it should 

 be held to strong light, and a hand magnifier we have 

 found to be of material assistance. 



Analysis for Sugar Standard Solution. Dissolve 

 51.98 grains of pure sulphate of copper in 500 grains of 

 <li stilled water. Keep this in a bottle by itself. 



Dissolve caustic soda in distilled water until the spe- 



