d proportion
of the urinary elements being known, any considerable change, either in
quantity or quality of its parts, bears unmistakable evidence of
disease. The invention of the microscope has provided increased
facilities for detecting diseases by examination of the urine. By the
aid of this wonderful instrument, we are enabled to discover with
absolute certainty the various urinary deposits characteristic of
different maladies; thus in Fig. 1, A represents in a general way the
sediment of abnormal urine as seen under the microscope. In division B
is represented oxalate of urea upon precipitation by oxalic acid.
Nitrate of urea is represented in division C. A deficiency of urea in
the urine, with albumen and casts present, is a most important guide in
the diagnosis of Bright's disease. The average quantity of urea present
during health is 21.57 parts in 1,000. The microscopic examination of
the urine, notwithstanding the distaste, and even contempt, which many
physicians manifest for such investigations, is pursued at the Invalids'
Hotel and Surgical Institute, with inestimable benefit to our patients.
It has revealed the existence of many serious affections, which, with
all our other modes of investigation, we might have been unable to
detect. It has also thrown light upon many obscure chronic diseases.

[Illustration: Fig. 2.]

We have already spoken of the marked changes effected in the urine by a
derangement of the digestive functions. It is a matter of surprise that
physicians generally pay so little attention to the urine when dyspepsia
is suspected, since all admit that an examination of that excretion
furnishes unmistakable evidence of the nature and complications of the
disease. In this way we are many times enabled to determine whether the
indigestion is caused by congestion or functional disease of the liver
or kidneys or by nervous debility. And when such cases are treated in
accordance with the indications furnished, increased success attends our
practice. In Fig. 2 highly magnified urinary deposits, which indicate
impairment of the digestive functions, are represented. The crystals are
composed of oxalate of lime and appear in the different forms shown in
the five sections, of octahedral, decahedral, round and dumb bell
shapes. The latter are formed in the kidneys, and are sometimes
discovered adhering to casts.

[Illustration: Fig. 3.]

INVALUABLE AIDS IN DETERMINING DISEASES OF THE KIDNEYS AND B