sect. 29.] MUSCULAR TISSUE. 6$ 



permeating them more especially shows ; which fluid, according to 

 Lehmann, has, for the most part, an acid reaction, and. contains 

 lactic, acetic, and butyric acid, also kreatin and. inosite ; and, as is 

 further proved by the frequent occurrence of physiological (in the 

 uterus) and pathological hypertrophies and atrophies of them. It 

 is uot known whether smooth muscles are ever regenerated, or 

 whether losses of substance are repaired by a similar tissue; 

 but new formations of them appear to occur in tumours of the 

 uterus. 



In the human body, the smooth muscular tissue nowhere forms 

 large isolated muscles, as in the case of the recto-penal muscles 

 of mammals, for example, but occurs either scattered in the con- 

 nective tissue, or in fhe form of muscular membranes. In both 

 cases, its bundles are either arranged parallel to each other, 

 or united to form networks; and, even in man, are connected 

 in many places with tendons of elastic tissue, as first detected by 

 me in the tracheal muscles, and in the cutaneous feather-muscles 

 of birds. It is found in the following places : 



1. In the alimentary canal, the smooth muscular tissue forms, 

 firstly, the muscular coat from the lower half of the oesophagus, 

 where smooth bundles are still intermingled with transversely 



striped fibres, to the internal sphincter of the anus; secondly, the 

 muscular layer of the mucous coat, from the oesophagus to the 

 anus; and, thirdly, individual muscular bundles in the villi. 



2. In the respiratory organs a muscular layer appears in the 

 trachea, on the posterior wall, and accompanies the bronchia as 

 far as their finest branches, as a complete circular coat. 



3. In the salivary glands, this tissue is found only in the Whar- 

 tonian ducts; and even there but scantily, and as an incomplete 

 layer. 



4. The liver possesses a complete muscular layer in the gall- 

 bladder, and smooth muscular tissue sparingly in the ductus 

 choledochus. 



5. The spleen, in many animals, possesses, in its envelopes and 

 trabecular, smooth muscular fibres intermixed with connective 

 tissue and elastic fibres. 



6. In the urinary organs the smooth muscles appear in the 

 pelvis and calices of the kidney and form a complete muscular 

 coat in the ureters and bladder, but, on the other hand, are found 

 but scantily in the urethra. 



7. The female sexual organs possess smooth muscles in the Fal- 

 lopian tubes, in the uterus, where their elements are enormously 



