30 GENERAL ANATOMY. 



It is dense, strong, and smooth, and only made adhesive by the black Pigment 

 which it deposits. 



Vessels and nerves of figurate, non-contractile uniting tissue. Vessels which 

 not only go through, but belong to the uniting tissue itself, are found in small 

 numbers in the strong structures (tendons, fibrous membranes) ; in larger in 

 the serous, the proper, and vascular membranes. Moreover, the quantity of 

 the vessels in one and the same membrane differs according to position (e. g., 

 the synovial membrane is more highly vascular at that part where it covers 

 the fibrous articular capsule, than upon the cartilage). 



Nerves are not found in the tendons (therefore they are not sensitive); 

 such as are found in the fibrous membranes do not probably terminate in 

 their substance. Whether nerves passing to serous membranes remain in 

 them, is also still doubtful, although it is a fact that peritonitis or pleuritis is 

 very painful. 



b. Contractile uniting tissue, that is, such as contracts upon irritation. To 

 this class belong : 



1. The external skin, Cut is and Corium (which see). 



2. Tunica dartos (see Splanchnol.), the wrinkled, reddish membrane on 

 the posterior surface of the Scrotum, of fibrous tissue, which consists of a 

 network of longer meshes, since the longitudinal bundles of uniting tissue 

 anastomose. (Septum Scroti consists of fibrous and common uniting tissue.) 

 It is remarkable for its vascularity and contractility, without muscular fibres. 



3. The tissue of the Corpora Cavernosa, of the penis and Clitoris, of the 

 corpus Spongiosum urethra, consists of a dense network of very extensible, but 

 strong, flattened, or roundish bundles of uniting tissue A fibrous sheath 

 envelopes and separates the two cavernous bodies. From it (tunica Albuginea) 

 larger or smaller laminae and septa extend inwards into the above-mentioned 

 network : each lamina is provided with a blood-vessel. 



4. The contractile tissue of the longitudinal and circular fibrous coat of the 

 veins and lymphatics (which see). 



The movement of the contractile tissues is not the consequence of a merely 

 physical elasticity. The external skin, when it contracts, becomes thickened, 

 shortened, and sinks in ; the openings of the hair follicles therefore pass out 

 (goose-skin), the hair stands on end. The same with the nipple. 



The Scrotal skin lies in transverse folds, when the longitudinal fibres of 

 Tunica Dartos contract. 



The Penis shrinks up, becomes harder and firmer, and the blood retires, 

 when the cavernous tissue contracts. 



The development of uniting tissue takes place from nucleated 

 cells, as may be demonstrated, which, according to Schwann, be- 

 come pointed in two opposite directions, and in this manner form 

 spindle-shaped fibres, from which finer ramifications pass of. 



Uniting tissue is very readily regenerated ; its lost substance is 

 replaced by a scar (cicatrix), which in loose parts is more firm, 

 in tendinous less so. 



The fluid (serum) which we find in uniting tissue, is no secreted 

 product from it, but is the fluid of the blood which penetrates the 

 parietes of the vessels therein, and so much the sooner collects 

 together the looser it is (e. g., in dropsy of the scrotum, about the 

 ankles, &c.) 



