NORMAL HISTOLOGY. 



are continually undergoing the changes effected by amoeboid move- 

 ment. These elements, in short, possess all the peculiarities of the 

 colorless blood-corpuscles with which, in fact, they are identical. 



In addition to the lymph-corpuscles, numerous fatty granules 

 are usually present within the plasma ; in the lymphatic vessels of 

 the intestinal tract the absorption of fatty matters is made conspicuous 

 by the presence of the chyle, an emulsion occupying the so-called 

 lacteals, or chyle- vessels ; these latter are not distinct tubes, but 

 only those portions of the lymphatic net-work which convey the 

 milky-looking chyle during certain stages of digestion. 



The sources of the lymph-corpuscles are those already con- 

 sidered in connection with the colorless cells of the blood, the lym- 

 phoid or adenoid tissues of the body being unquestionably the most 

 important and prolific seats for the production of these elements. 

 The presence of a few cells within the lymph-radicles, between their 

 commencement and the first masses of adenoid tissue occurring on 

 their course, is due to the entrance within the vessels of migratory 

 cells from the surrounding connective tissue ; only after the lymph- 

 stream has passed through considerable masses of lymphoid tissue 

 do the corpuscles appear with profusion. 



THE LYMPHATIC TISSUES. 



Lymphatic, lymphoid, or adenoid tissue usually occurs as 

 circumscribed masses known as lymphatic nodules or "glands;" 

 in certain localities, however, as in parts of the 

 mucous membranes of the larynx, the pharynx, 

 the stomach, the intestines, etc., ill-defined 

 masses of diffuse lymphatic tissue occur. 

 These are recognized as aggregations of small 

 round cells, fading away among the surround- 

 ing structures. 



Lymphatic tissue, wherever found, is com- 

 posed structurally of two elements the deli- 

 cate connective-tissue reticulum, on the 

 surface of the fibres of which plate-like, often 

 stellate, connective-tissue corpuscles are applied, 

 and the small round cells contained within 

 the reticulum. These elements the lymphoid 

 or adenoid cells become the lymph-cor- 

 puscles and the colorless blood-cells on their 

 escape from the denser reticulum into the 

 lymph-current and their subsequent entrance 

 into the blood. 



The variations in the compactness with which the cells are lodged 



FIG. 141. 



Elements of adenoid tissue 

 from partially brushed sec- 

 tion of lymphatic gland of 

 child : a, fibres of reticulum ; 

 b, lymphoid cells; c, ex- 

 panded connective - tissue 

 plate. 



