i in 301 



'(> tin- left pelvic region, win-re it is contimml into the 

 rigmoid flexure and m-tum. Then-ton- then- are distinguishable in 

 the colon, even in tin- third month, tin- curum, the transverse and 

 tin- descending colon. An aM-ending colon is -till wanting. It is 

 formed in the succeeding months (lig. 165 B) hy tin- gradual .-inking 

 o!,.\\n of the ccecum, which was at iir>t undi-r tin- liver, until in the 

 si-MMith month it is below the right kidney, and from the eighth 

 month onward d- > .-mis past the crest of tin- ilium. 



Meanwhile the ccecum has increased in length and toward the 

 end of pregnancy is a rather large appendage at the place of tran- 

 sition from the small to the large inn-Mine. It early exhil>i 

 want of uniformity in development (fig. 165 B bid). The terminal 

 part, whirh often embraces more than half its length, does not keep 

 pace in its growth with the more rapidly enlarging proximal portion; 

 t he former is designated as the appendix vermiformis, the latter as the 

 ft, At the time of birth the vermiform appendage is still not 

 >o sharply differentiated from the coecum as it is a few years later, 

 when it has been converted into an appendage of the size of a goose- 

 quill and 6 to 8 cm. long. 



\V it hin the region embraced by the bends of the large intest int. 

 the small intestine, which is derived from the descending arm of 

 the loop, is disposed in more and more numerous folds owing to 

 its extensive growth in length (fig. 165 B). 



At lir>t all regions of the intestine from the stomach onward are 

 so united to the lumbar region of the vertebral column by means of 

 a common mesentery (mesenterium commune) that they can move 

 freely (fig. 165 A and B). The mesentery is naturally influenced by 

 the increase in the length of the intestine, inasmuch as its line of 

 insertion on the intestine exceeds in length many times the line of 

 origin at the vertebral column (radix mesenterii), and is thereby laid 

 into folds like a frill. Such an arrangement of the mesentery i> 

 found to be the permanent condition in many Mammals, as in the 

 Dog, the Cat, etc. 



But in the case of Man, from the fourth month onward, the 

 arrangement of the mesentery is much more complicated. T 



changes which may le briefly chura-t-ri>ed as j/rocesaes of 

 and concrescence of certain portions of the me8ent'rinl In 

 contiguous parts of the peritoneum, either of th ;>o-teiior wall 

 of the body-cavity, or of neighboring organs. They affect the 

 nit >entery of the duodenum and colon, which i> alway> present in 

 the lirst half of embryonic developnu-nt. 



