320 SPECIAL HISTOLOGY. 



4.— OF THE BLOOD AND THE LYMPH. 



§ 220. 



Every part of the vascular system contains in its interior 

 a special liquid, consisting of a fluid and numerous morpholo- 

 gical particles, and which, according to its colour, its occurrence 

 in one or other division of the system, and its other pro- 

 perties, is distinguishable on the one side into white and red 

 blood, and lymph or chyle; and on the other, into blood in the 

 more strict sense of the term. Histology is concerned only with 

 the description of the morphological elements existing in these 

 fluids, among which the blood- and lymph-corpuscles are by far 

 the most important, leaving the description of their other 

 conditions to physiology. 



§221. 



The lymph and the chyle, like the blood, consist of a plasma, 

 which coagulates out of the vessels; and of morphological 

 elements, including elementary granules, nuclei, colourless cells, 

 and red blood-corpuscles, which, however, are not found in all 

 parts of this vascular system, nor everywhere in equal quantity. 

 The elementary granules are immeasurably minute granules, 

 which, as has been shown by H. Muller, consist of fat and a 

 protein-envelop, and are contained in vast numbers in milky 

 chyle, whose colour is owing to them alone, whilst, in the more 

 colourless lymph they are either wholly wanting, or are rare 



processes, fitted together into a soft tissue, in which the capillaries of the medullary 

 substance lie. Round cells in different stages of development follow them, resembling 

 the lymph-corpuscles, and forming the immediate limit of the fine, irregular, fre- 

 quently anastomosing canals, which render the medullary substance as porous as a 

 sponge. The whole gland is inclosed in a membrane, which, as Heyfelder observed, 

 is composed of connective tissue and smooth fibre-cells, and sends sheaths in towards 

 the medullary substance, whereby imperfect compartments are formed, in which the 

 glandular elements lie. The chyle of the vasa inferentia traverses the glandular 

 elements, enters the pores of the medullary substance, and passes thence on the opposite 

 side, between the glandular elements to the vasa efferentia. " I have never" (says 

 Briicke) " observed the fat-drops of the chyle enter into the interior of the glandular 

 elements, which appear to be merely bathed with the fluid part of it. On the other 

 hand, the cells which are formed in the glandular elements pass as lymph-corpuscles 

 into the chyle." — Eds.] 



