i8 IMMUNITY IN HEALTH 



As has been said above the small glandular lympho- 

 cytes are probably derived from the large ones in the 

 lymphatic glands. The great majority pass via the 

 efferent lymphatic channels (and perhaps also directly) 

 into the blood where as small lymphocytes they con- 

 stitute twenty per cent, of the total white corpuscles 

 or 1,400 per cubic mm.* 



Both small and large glandular lymphocytes func- 

 tion principally as scavengers, being provoked to activ- 

 ity by slightly different stimuli, t 



The large glandular lymphocytes may join together 

 to form giant cells. Sometimes one large lymphocyte 

 engulfs other cells and various debris and attains to a 

 very great size. It may ultimately die leaving an inert 

 pigmented mass in the gland. 



Lymphoid structures do not everywhere show con- 

 struction of such definite unit elements as is recorded 

 above. Thus in the medulla of an interstitial lymph- 

 atic gland the small and large glandular lymphocytes 

 are mingled indiscriminately. The lymph nodules every- 

 where become less distinct in very old animals (Baum 

 and Halle, 1908). Clearly marked lymph nodules Tnake 

 up the cortex of every interstitial lymphatic gland. 

 They are also placed eccentrically at intervals along 

 the arterioles of the principal haemo-lymph gland, the 

 spleen. 



Lymph nodules are present singly or in groups in 

 all the siTbepithelial lymphatic glands. 



After considering this unit-material or element of 

 lymphatic glands, it remains to consider the manner 

 in which these elements are combined to form the 

 different lymphatic organs. 



* The researches of Goodall and Gulland seem to show that many 

 lymphocytes are also formed in the bone marrow. 



t It is most remarkable that the glandular lymphocytes are both 

 motile and phaf^ocytic. The small lympliocytes in the blood are 

 usually described as non-motile and non-phagocytic. 



