STRUCTURE OF LYMPHATIC GLANDS. 441 



mediately after they have penetrated the capsule of the gland, 

 it is found to become thicker and more opaque. In the short 

 dilated anastomosing branches which form the intra-glandular 

 network this tunic has become so thick and opaque, that the 

 vessels will no longer transmit the light, and appear as if they 

 were stuffed full of a granular matter. When these thickened 

 and dilated vessels are cut, torn, or broken, so as to display 

 their structure, it may be observed that two parts enter into 

 their composition an extremely fine external membrane, and 

 a thick granular substance, which lines the membrane. 



The external membrane is extremely thin and transparent. 

 In its substance there are arranged, at regular distances, 

 ovoidal bodies, so placed that their long diameters are all in 

 the same direction. The distance of these bodies from one 

 another is somewhat greater than their long diameters. They 

 are imbedded in the substance, and form a part of the mem- 

 brane. They are hollow, and contain one or more rounded 

 vesicles grouped together in their interior. I have seen 

 portions of this membrane, after it has been acted upon by 

 acetic acid, present an appearance of being broken up into 

 flat semi-transparent scales, united by their edges each scale 

 consisting of one of the nucleated ovoidal bodies, and a 

 portion of the surrounding membrane. 



The thick granular substance which is attached to the 

 internal surface of the membrane just described, is composed 

 entirely of nucleated particles, closely packed together, and 

 cohering to one another. The thickness of this layer of 

 granular substance is so considerable as to render the vessel, 

 of which it is a part, almost opaque, encroaching on its cavity, 

 and leaving a comparatively narrow canal for the passage of 

 the lymph and chyle. This canal appears to be somewhat 

 irregular, in consequence of the greater exuberance of the 

 granular substance in some spots, and its deficiency in others. 

 This circumstance also accounts for the greater transparency 



