THE URINE. 801 



occurs, we are unable to decide where the morbid condition is 

 situated. 



As a general thing, we know that in the male genito-urinary 

 tract the urethra, the bladder, the ureters, and the pelves of the 

 kidneys have a lining of stratified epithelia ; while all glands in 

 connection with the tract, the mucous glands, the prostate, and 

 their ducts, including the ejaculatory ducts, have a single layer 

 of epithelia. A single layer is present also throughout all the 

 uriniferous tubules. The largest epithelia are found in the 

 urethra ; next in size are those of the bladder, then follow the 

 epithelia of the pelves of the kidneys, and the smallest epithelia 

 come from the kidneys proper. It is maintained that the epithelia 

 of the bladder, of the ureters, and of the pelves of the kidneys, 

 are identical in size and shape. By scraping off the epithelia of 

 the above-named organs, this idea appears correct ; but, if we 

 study the epithelia in situ, we arrive at the conviction that the 

 epithelia, upon approaching the kidneys, very gradually decrease 

 in size from without inward. Middle-sized epithelia of the bladder 

 are identical with the largest pelvic epithelia, and, therefore, are 

 of no value for diagnosis, while the average epithelia of the pelves 

 are distinctly smaller than those of the bladder. The caudate, 

 double caudate, and lenticular forms of epithelia are far more 

 prevalent in the pelves and calices than in the bladder, and well 

 adapted, therefore, for a diagnosis of pyelitis. 



In the female genito-urinary tract, the epithelia of the vagina, 

 the cervical portion of the uterus, the urethra, bladder, ureters, and 

 pelves, are stratified. The epithelia of the mucosa of the uterus 

 are columnar and ciliated, forming a single layer ; the kidneys 

 also show columnar, flat, and cuboidal epithelia in a single layer, 

 the same as in the male. Flat and cuboidal epithelia of the 

 kidney, in the urine of either sex, cannot be distinguished, but 

 the columnar epithelia are distinctly marked formations. Besides, 

 in either sex, flat, horny epithelia from the fingers and the external 

 genitals may be found, having a jagged contour, a high refrac- 

 tion, a homogeneous appearance, and no nucleus. They often 

 are studded with particles of dust or granules of fat. Epidermal 

 scales from the inner surface of the prepuce and that of the labia 

 majora are paler, and often hold granules of fat (sebaceous 

 material). 



The diagnostic value of the epithelia in urine, if mingled 

 with pus-corpuscles, is as follows (see Fig. 366) : 



Male Urine. The largest flat epithelia from the urethra are 

 51 



