TESTICLE, one of the two genital glands of the male in which the spermatozoa and some other of the constituents of the semen are formed; a testis. The term is also applied to either of the posterior tubercles of the optic lobes or corpora quadrigemina. The testicle proper lies in the scrotum, is of an oval form and is mostly invested with a pouch or closed sac of serous membrane, the tunica vaginalis, derived from the peritoneum during the descent of the gland from the abdomen into the scrotum. The organ consists of a central por tion or body, an upper enlarged extremity, the globus major or head, and a lower extremity, the globus niinor or tail. Lying upon the pos terior border of the testicle is a long narrow flattened body, the epididymis. To this border is attached the spermatic cord, composed of arteries, veins, lymphatics and nerves, con nected together by areolar tissues and invested with fascia:. This cord ends in the internal abdominal ring. It is accompanied by the vas deferens, the excretory duct of the testis (a continuation of the epididymis), which passes through the ring into the pelvis to the base of the bladder, where it unites with the duct of the vesicula seminalis to form the ejaculatory duct, which terminates in a slit-like orifice in the prostatic portion of the urethra. Underneath the tunica vaginalis is the tunica albuginea, or fibrous covering of the testicle, and beneath this coat is the tumca vasculosa, or vascular tunic, composed of a plexus of blood vessels held together by delicate areolar tissue. The glandu
lar structure of the testis consists of from 250 to 400 lobules, each composed of from one to three or more minute convoluted tubes, the tubuli seminiferi. These tubules unite into larger tubes, which carry the seminal fluid from the testis to the epididymis.
The testicle is subject to hypertrophy, atrophy, injuries, acute or chronic inflammation, cystic diseases, fibroma, malignant disease and neuralgia. Inflammation of the testicle (or chitis), as that of the epididymis (epididymitis, q.v.), is usually attended with much pain and swelling and a feeling of weight and great dis comfort. The use of a properly fitting sus pensory bandage affords much relief ; but the treatment of diseases or disorders of the testicle should be entrusted to a physician. (See also SPERMATOZOA). The removal of both testicles renders a man impotent —a eunuch. Castra tion is the surgical operation of removing the testicles, and is performed on horses, steers, etc., to render them more docile and tractable. It is generally recognized that castration re duces the will power and interferes with various brain functions.