A Manual of Clinical Diagnosis by Means of Microscopical and Chemical Methods; For Students, Hospital Physicians and Practitioners (Paperback)

This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1902 edition. Excerpt: ...the point for which the instrument is registered, viz., 15 C. According to Bouchardat and Mercier, this method is not strictly accurate, and the following table has been constructed by which the proper corrections can be readily made: Example.--Supposing the specific gravity to have leen 1.0.30, at a temperature of 20 C, it would be necessary to add 0.9 to 1.030, making this 1.0309; at a temperature of 10 C, it would similarly be necessary to subtract 0.5. Determination of the Solid Constituents.--As indicated above, the amount of solids can be calculated with a degree of accuracy sufficient for clinical purposes by multiplying the last two figures of the specific gravity by 2; the number obtained indicates the amount of solids in every 1000 c.c. of urine. If greater accuracy is required, the following method may be employed: Five c.c. of urine, accurately measured, are placed in a watchcrystal containing a little dry saud (sand and crystal having been previously weighed); this is placed over a dish containing concentrated sulphuric acid, and under the receiver of an air pump which has been made perfectly air-tight by thoroughly lubricating the ground-glass edge of the bell with mutton tallow and applying the bell with a slightly grinding movement to the ground-glass plate. The receiver is now exhausted and the urine allowed to remain in the vacuum for twenty-four hours, when the bell is again exhausted and left for twenty-four hours longer; at the end of this time the crystal is weighed, the difference between the two weights obtained indicating the amount of solids in 5 e.c. of urine, from which the percentage and total amount are readily calculated. The slight loss of ammonia which results when this method is employed scarcely affects...