SECTION OF THE THYMUS BODY. 177 



THYMUS BODY. 



The thymus body (frequently and improperly called a gland) is an 

 adjunct to the lymphatic system of in man foetal and infantile 

 life ; disappearing, by an atrophic process, at or before the age of 

 puberty. 



It is enveloped by a fibrous capsule, partitions from which sub- 

 divide the organ into lobes and lobules. The lobules are generally 

 subdivided into follicles, which are irregularly sized and shaped, 

 while tending to an ovoid form. 



It is in connection with the general lymphatic system by peri- 

 pheral, afferent lymph-channels ; and by efferent vessels which emerge 

 from the hili of the lobes the lymph having meanwhile traversed 

 the mesh-like structure of adenoid tissue composing the follicles. 



The blood-vascular system is in the form of a nutritive supply; 

 the larger vessels occupying the fibrous framework, and sending 

 branches into the follicles. The capillary plexuses are more 

 abundant in the peripheral portion of the follicles. The blood is 

 collected in the venous channels of the central or medullary area, 

 and emerges from the organ by the veins which accompany the 

 efferent lymphatics. 



PRACTICAL DEMONSTRATION". 



The organ should be obtained from a still-born infant, divided in 

 small pieces, and hardened rapidly in strong alcohol. Sections 

 may include an entire lobe, and be stained with hgema. and eosin. 



SECTION OE THE THYMUS BODY FROM AN INFANT 

 AFTER DEATH ON THE SIXTEENTH DAY. (Fig. 117.) 



OBSERVE: 

 (L.) 



1. The fibrous capsule. 



2. Division by prolongations of 1 into somewhat spherical 

 lobes. 



3. Subdivision of 2 into lobules. 



4. Subdivision of 3 into follicles. (Note that these are not uni- 

 formly outlined by the connective tissue.) 



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