126 



THE ESSENTIALS OF HISTOLOGY. 



nodular masses which are like the cortical nodules of a lymphatic 

 ^gland, and may, like those, be partially surrounded by a lymph-sinus. 



In the spleen also a large amount of lymph- 

 oid tissue is found sheathing the smaller 

 arteries, and also expanded into nodular 

 masses (Mcdpighian corpuscle* of the spleen). 

 In these organs it will be studied subse- 

 quently. 



Lymphoid tissue also occurs in consider- 

 able amount in the serous membranes, 

 especially in young animals ; in the adult 

 it is often transformed into adipose tissue. 

 The tissue is generally developed in con- 

 nection with lymphatic vessels, an accumula- 

 tion of retiform tissue and lymph-cells taking 

 place either external to arid around the 



lymphatic (perili/mphatic nodule) ; or the lymphatic is dilated into a 

 sinus and the formation of lymphoid tissue occurs within it* 1 (endo- 

 lympliatic nodule). 



FIG. 150. ELEMENTS OP THE 

 THYMUS. (300 diameters.) 

 (Cadiat.) 



a, lymph -corpuscles ; b, con- 

 centric corpuscle. 



