MUCOUS MEMBRANE OF THE SMALL INTESTINE 



213 



Fi S- 45- Patch of Peyer (Sappey). 

 i, i, i, patch of Peyer; 2,2, folds 



ferent sizes. These patches usually are found in the ileum. The num- 

 ber of the solitary glands is variable and they are sometimes absent. 

 The patches of Peyer are situated in that 

 portion of the intestine opposite the attach- 

 ment of the mesentery. They are likewise 

 variable in number and are irregular in size. 

 They usually are irregularly-oval in form, 

 and measure half an inch to an inch and a 

 half (12.7 to 38.1 millimeters) in length by 

 three-fourths of an inch (19.1 millimeters) 

 in breadth. Sometimes they are three to 

 four inches (7.6 to 10.1 centimeters) long, 

 but the largest always are found in the lower 

 part of the ileum. Their number is about 

 twenty, and usually they are confined to the 

 ileum ; but when they are very abundant, 

 for they sometimes exist to the number 

 of sixty or eighty, they may be found in 

 the jejunum or even in the duodenum. tweensomeof the folds; 5,5,5,5,5, 



Two varieties of the patches of Peyer have |; '\^SS^^. .^ 

 been described; in one, the patch is some- solitary glands ; s, s, solitary glands 



on the valvulae conniventes. 



what promi- 

 nent, its surface being slightly raised above 

 the general mucous surface ; in the other, 

 the surface is smooth, and the patch is 

 distinguished at first with some difficulty. 

 The prominent patches are covered with 

 mucous membrane arranged in folds some- 

 thing like the convolutions on the surface 

 of the brain. The valvulae conniventes 

 cease at or near their borders. These are 

 the only patches that are commonly de- 

 scribed as the glands of Peyer, the others, 

 which may be called the smooth patches, 

 Fig. 46. Patch of Peyer seen from frequently being overlooked. The latter 





are covered with a smooth, thin and closely 

 adherent mucous membrane. Their follicles 



its attached surface (Sappey). 



i, i, serous coat of the intestine; 

 2, 2, 2, 2, serous coat removed to show 



the patch; 3, 3, fibrous coat of the in- are sma ll and abundant The borders 



testine; 4, 4, patch; 5, 5, 5, 5, 5, 5, 5, . . . 



5, vaivuiae conniventes. of these patches are much less strongly 



marked than in those of the first variety. 



As they are seen only on close examination and as they are the only 

 patches present in certain individuals, it is sometimes said that the 



