501 



ferior surface by interfering with the pressure of the intestinal coils 

 from below. That the inferior surface is not produced by traction of 

 the transverse mesocolon along its attachment corresponding to the 

 anterior border of the pancreas is shown by the fact that the body 

 of the pancreas is still distinctly prismatic in the earher foetuses before 

 the mesocolon and posterior mesogastrium (great omentum) have be- 

 come adherent to each other. The earlier specimens (chiefly from the 

 Mall collection) which I have examined seem to indicate that the body 

 of the pancreas is at first somewhat flattened, especially in its outer 

 l)ortion, between the stomach anteriorly, and the suprarenal body and 

 kidney posteriorly. The inferior surface is soon developed, however, 

 as a result of contact with the intestines which push up from below ^). 

 This occurs first, as a rule, on the inner portion of the body, which 

 comes into contact with the duodeno-jejunal flexure about the be- 

 ginning of the third month. Somewhat later the inferior surface is 

 developed in the outer part of the pancreas through pressure against 

 the jejunum and splenic flexure of the colon. The youngest specimen 

 in which I have found the body triangularly prismatic throughout was 

 5,0 cm crown-rump length. In the foetuses of the third and fourth 

 months the three surfaces, anterior, posterior, and inferior, often ap- 

 pear nearly equal in width. This condition may also persist through- 

 out foetal life {d. Fig. 9), but in most of the older foetuses the in- 

 ferior surface is found relatively narrower, and the anterior and 

 posterior surfaces wider. This flattening in the dorso-ventral direction 

 is best marked in the outer half of the body of the pancreas, and is 

 probably due to the pressure of the body of the stomach, which not 

 only increases in size, but also becomes more or less distended through 

 the accumulation of a mucous-like fluid in its cavity. 



In order to determine experimentally the effect of a distended 

 stomach on the form of the pancreas, I distended the stomach of three 

 full-term foetuses through the oesophagus, and then hardened them in 

 this condition by intravascular injection of formalin. In the first case, 

 the fluid injected into the stomach was allowed to pass also into the 

 intestines, so that they also became distended (the anus being ligated 

 to prevent the escape of the fluid). A sagittal section made through 

 the left side of the body, after hardening, is represented in Fig. 10. 



1) In embryos of the ninth week, and earlier, I find the postero- 

 inferior aspect of the pancreas related to the npper and anterior sur- 

 face of the sexual anläge (testis or ovary). The contact does not seem 

 intimate enough to produce a distinct surface, however. 



