striped muscle cells. Beneath this coat is a loose fibro- 

 elastic coat, the submucosa, in which several quite large 

 arteries and veins will be seen in section. The muscle 

 coat is composed of an inner circular and an outer longi- 

 tudinal layer of non-striped muscle tissue. The serous 

 coat is seen as a thin layer of fibrous tissue, covered on the 

 outer surface by a layer of endothelial cells. Sketch the 

 section by the side of the drawing of the pyloric end of the 

 stomach. 



(g) Small Intestine Showing Peyer's Patch. 



A piece of the small intestine known to contain a Payer's patch 

 was hardened in mercuric chloride, stained in Delafield's hamiatoxy- 

 lin, embedded in paraffin, and sectioned. Fix and mount in 

 balsam. 



Study under low power. Observe the several nodules 

 of simple adenoid tissue in the mucosa^and submucosa, 

 pushing aside the crypts of Lieberkiihn, and often coming 

 up under the epithelial lining of the intestine and causing 

 an elevation of the epithelial layer. Sketch a portion of 

 the intestine showing a lymph nodule as seen under low 

 power. 



(h) Injected Small Intestine. 



The mesenteric artery of a c<4 was injected with gelatine- 

 carmine, hardened in alcolml, stained .in Delatield's hsematoxylin, 

 embedded in paraffin, and cross-sectioned. Fix and mount in 

 balsam. 



Use low power. Note the arrangement of the in- 

 jected vessels in the muscular coat, in the submucosa, 

 about the crypts of Lieberkiihn, and in the villi. Sketch 

 a portion of the wall under low power. 



(i) Large Intestine. 



Pieces of the large intestine of a dog were hardened in alcohol, 

 stained in borax carmine, embedded in paraffin, and sectioned. 

 Fix to the slide, and mount in balsam. 



Notice that in the hirge intestine no villi are found. 

 Simple tubular glands, the crypts of Lieberkiihn, are 

 observed. They are placed vertically in the mucosa, and 

 are lined by a single layer of short columnar cells, the 

 great majority of these appearing as goblet cells. Sketch 

 by the side of the small intestine as above directed. 



