In what organ of the body would you find Bowman's capsules?

Bowman's capsule (or the Bowman capsule, capsula glomeruli, or glomerular capsule) is a cup-like sack at the beginning of the tubular component of a nephron in the mammalian kidney that performs the first step in the filtration of blood to form urine. A glomerulus is enclosed in the sac. Fluids from blood in the glomerulus are collected in the Bowman's capsule and further processed along the nephron to form urine.

The process of filtration of the blood in the Bowman's capsule is ultrafiltration (or glomerular filtration), and the normal rate of filtration is 125 ml/min, equivalent to 80 times the daily blood volume. Any small molecules such as water, glucose, salt, amino acids, and urea pass freely into Bowman's space, but cells, platelets and large proteins do not.

Bowman's capsule is named after Sir William Bowman (1816-1892), a British surgeon and anatomist.  However, thorough microscopical anatomy of kidney including the nephronic capsule was described by the Ukrainian surgeon and anatomist from the Russian Empire, Prof. Alexander Shumliansky (1748-1795), in his 1788 doctoral thesis "De structura renum: Tractatus physiologico-anatomicus" ("About Kidney Structure: an Physiological-Anatomical Treatise," in Latin); thus, much prior to Bowman.