After intramuscular injection, the normal appearance time is nearer 10 minutes, and the normal elimination is 30-40% in 30 minutes, and totals of about 50% (40-60) for 60 minutes, and about 80% (60-85) for 2 hours, or 20-25% during the second hour. If the appearance time is not determined, it is customary to allow for it, collecting the first hour’s specimen at 70 minutes after injection of dye and the second hour’s 60 minutes later.
Impairment of kidney function, of course, increases appearance time and lessens excretion, serious cases not unusually excreting less than 1% during two hours.
When the question of the kidney involved arises, the urine must be taken by ureteral catheterization or by a separator.
Starches and Fibres.—In examining urinary sediments it is important to be familiar with the various textile fibres and starch grains which are so frequently present, the fibres coming from the clothing and the starch grains from dusting powders. Wool fibre fragments show bark or scale-like imbrications and are round. Cotton fibres are flattened and twisted, while linen ones show a striated flattened fibre with frayed segments as of a cane stalk. Silk shows a glass-like tube with mashed-in ends.
Corn and rice grains are the most common of the starch grains and their nature is immediately disclosed by their blue color when mounted in iodine.
Affections of the Genito-urinary Organs
In blackwater fever we have marked pain in the region of the kidneys due to the plugging of the tubules with haemoglobin casts. Vesical tenesmus and pain along the ureters may also be present.
In malaria Thayer states that nephritis occurs in about 2% of malignant tertian cases.
In bilharziasis the kidneys are involved secondarily—the change being brought about by stone in the bladder and cystitis leading to hydronephrosis and pyelonephritis.
Cases of cystitis occurring in dysentery have been reported which showed amoebae in the sediment of the urine. Such cases probably were connected with recto-vesical fistulae caused by amoebic ulceration.