Journal of Applied Microscopy. 575 



fully developed the writers consider to be identical with the mononuclear leuco- 

 cyte of Ehrlich. 



In the follicles, in addition to the typical lymphocytes, is found an almost 

 equal number of cells closely resembling them but with a larger nucleus, in 

 which the chromatin is not so compactly arranged. A few small mononuclear 

 cells and a few eosinophiles are also found. 



Some follicles are uniformly composed of lymphocytes in which no evidence 

 of karyokinesis is seen. Other follicles have a peripheral zone composed of 

 lymphocytes and a " clear center " (germinative center) made up of what the 

 writers call mononuclear leucocytes with numerous karyokinetic figures. There 

 is no sharp line between these two kinds of cells. The protoplasm of some of 

 the larger cells in these centers contain fragments of chromatin which would 

 indicate that they are phagocytic in character. 



In the subcapsular sinuses are found lymphocytes, mononuclear leucocytes, 

 small and large eosinophiles, and cells of the reticulum, which are sometimes 

 seen to have engulfed red blood corpuscles and lymphocytes. In the cavernous 

 sinuses practically the same cells, with occasionally mast cells, are found, though 

 the phagocytic cells are not so common. 



Never in the normal lymph node (guinea-pig and rabbit), say the writers, 

 are polynuclear leucocytes found. The lymph nodes used for study were those 

 of the guinea-pig and rabbit, and differed little according to location. The 

 bronchial nodes had a greater vascularity, and the mesenteric showed a few 

 slight differences in their reticulum. 



In the cat the follicles are very abundant. In the dog there is an abundance 

 of connective tissue. 



In man the capsule is less developed and cannot be seen penetrating the 

 node. There are very few eosinophiles. The " germinating centers " of the 

 follicles are much more prominent in the child than in the adult. In the latter, 

 connective tissue proliferation is prominent and there is little evidence of kary- 

 okinesis. In old age a true atrophy takes place. 



The function of the lymph node is to form the lymphocytes of the blood, and 

 in the rabbit and guinea-pig probably the eosinophiles. This function is 

 increased in infection as is also the production of phagocytic cells which engulf 

 not only bacteria, but also dead cells and other foreign debris. R. m. p. 



Lochte. Zur Kenntniss der epithelioiden Urn- Twenty cases of persistent thymus in 

 wandlung der Thymus. Centrlb f. AUg. ^j^g ^dult were Studied. In one case, a 

 Path. u. Path. Anat. 10: No. 21, 1899. 



male aged twenty-one who died of 



septic purpura, the gland was almost entirely composed of large epithelioid cells 

 with broad protoplasmic borders and large oval or round nuclei. The cells lay 

 in an alveolar connective tissue. These cells probably arise from the cells of 

 the reticulum. 



Occasionally these cells showed unmistakable transformation from connective 

 tissue cells. Some had two, three, or more nuclei. Small collections of 

 lymphoid cells with colloid Hassall's bodies were found lying between the epithe- 

 lioid cells. 



