136 GLANDS. 



hepatic cells, the internal mass sprouts into numerous 

 tubular branches which, penetrating the substance of 

 the outer mass, constitute the system of biliary 

 ducts. Whilst these changes are taking place, the 

 original primordial cells, of which the masses were 

 composed, undergo various metamorphoses which 

 result in the formation of the several tissues consti- 

 tuting the substance of the gland. 



preparations. The preparations on which the structure of the 



liver is best studied are very delicate sections of the 

 fresh liver, and also of livers injected with colors 

 ground in oil and diluted- with essence of turpentine. 



3 U tfe e inteft?ne d 8 8 SECT. IV. DUCTLESS FOLLICLES AND BLOOD GLANDS. 



The most simple in their structure of this class of 

 organs are the solitary glands of the intestinal canal. 

 These are little spherical bodies, situated deeply in 

 its mucous membrane, and varying from half a line 

 to one line in diameter. Their walls consist of fibroid 

 membrane studded thickly with plasmatic ceils. Their 

 contents, greyish in color, and of a solid consistence, 

 are made up of a quantity of rounded globules, from 

 aFifth to T^jth of a line in diameter, and bearing a 

 very close resemblance to the cells contained in the 

 interior of the lymphatic glands. Numerous blood- 

 vessels ramify upon their exterior, and then, penetrat- 

 ing their walls, converge towards the centre of each 

 follicle. Externally to the follicle they anastomose 

 freely, but towards its centre they form a great number 

 of loops, which, when filled by injection, present a very 

 beautiful appearance (PL XXVI. fig. XIII. 2). Kol- 

 liker has found nerves in the follicles of the tongue, 

 , according to this author, E. Weber has also 



