204 



MICROSCOPIC ANATOMY OF THE ORGANS. 



smaller lymphatics in the submucous tissue (Sudler). These 

 are shown in Fig. 158. 



The nerves of the gall bladder are both medullated and non- 

 medullated. Sympathetic fibres, according to Huber, supply 

 the blood-vessels and smooth muscle of the wall. Dogiel has 



FIG. 158. 



Keconstruction of wall of a dog's gall-bladder. (Sudler.) A, artery ; V, vein ; L, lym- 

 phatic. X 60. 



described ganglion cells in this situation. According to Huber, 

 medullated sensory fibres are found near the large arteries and 

 distributed to the mucous membrane. 



The development of the various structures in the liver has 

 not been worked out thoroughly. The lobule is formed late in 

 the growth of the embryo. The portal and hepatic veins are 

 at first at opposite ends of the organ, and the regions of tissue 

 around them have nothing to do with one another. Later on, 

 by a shifting of some sort, and a new formation of vessels, they 

 come to have the intimate relation seen in the adult liver. 

 Much of this change has taken place already in the human 

 embryo by the fourth week. 



As the diverticula grow out from the mid-gut of the embryo 

 to form the first rudiments of the liver a primitive bile duct is 

 established. By a branching of this the large ducts of the 

 organ are formed, but it is uncertain whether the bile capil- 



