URJNE. 171 



The urethra is surrounded in its prostatic portion by the 

 prostate ; in its penile portion by the corpus spongiosum ; be- 

 tween these two portions is a short interval, the membranous 

 portion, in which the urethra is supported in fibrous tissue. 



The urine is a clear, homogeneous, serous secretion, contain- 

 ing a slight amount of mucus. A very few adventitious ele- 

 ments may be normally present detached epithelium-cells, 

 mucous corpuscles, stray leukocytes, and spermatozoa. In 

 abnormal conditions a variety of organic formed elements and 

 crystalline or amorphous solid substances may appear. 



