190 



PRACTICAL HISTOLOGY. 



[XV. 



FIG. 162. Isolated Smooth 

 Muscular Fibres, 

 acid, x 300. 



2. Muscle-Cells from the Frog's Bladder (|_ and H). Distend 

 the frog's bladder with dilute alcohol thus. Transfix the skin on 

 each side of the anus with two pins, and tie round them a thread so 

 as to occlude the anus ; open the abdomen, 

 make a slit into the large intestine, clear out 

 any residues it may contain, and inject dilute 

 alcohol through the intestine into the blad- 

 der. When the latter is full, ligature it at 

 the neck, and suspend it for twenty-four 

 hours in a large quantity of dilute alcohol. 

 Then open the bladder, and with a camel's- 

 hair brush pencil away all the lining epi- 

 thelium. Stain a portion of the bladder in 

 logwood and mount it in balsam, or stain 

 in picro-carmine and mount it in Farrant's 

 solution. 



(a.) Observe the thin membrane, traversed 

 in every direction by thicker or thinner tra- 

 beculaB of smooth muscle (fig. 163, a). The 

 trabeculae consist of numerous long fusiform 

 Nitric nucleated cells (c) the nuclei, long, narrow, 

 and oval. Some of the cells are triradiate 

 (/;). These are what S. Mayer has called atypical cells. Oval nuclei 

 with blunter ends are seen in the fibrous covering of the bladder (d). 

 They are the nuclei of connective-tissue ceils. 



3. T.S. Non-Striped Muscle 

 (H). This is obtained by mak- 

 ing transverse sections of the 

 circular muscular coat of the 

 small intestine (cat), previously 

 hardened in chromic acid and 

 spirit, or Miiller's fluid. Stain 

 a section in haBmatoxylin and 

 mount in balsam. 



(a.) Observe polygonal areas 

 of unequal size, mapped out 

 from each other by a refractive 

 (fig. 164) cement substance. 

 Each area corresponds to the 

 transverse section of a tibre. 

 Some of the areas contain a 

 nucleus (n), others not. Sur- 

 rounding groups of these areas are fine septa of connective tissue 

 (s), which map out the fasciculi or bundles of cells. The fibres are 

 arranged in bundles or fasciculi, each surrounded by an envelope of 



FlG. 163. Bladder of Frog. a. Large strands 

 of smooth muscle ; b. Triradiate, and c. 

 Fusiform muscle-cells ; d. Nuclei of con- 

 nective-tissue corpuscles. 



