292 DR A. J. WHITING ON THE 



five in a section. Coarsely granular protoplasmic corpuscles occur in the follicles 

 and in the pulp ; in the latter are also numerous nucleated red cells and- a few erythro- 

 blasts. 



In the spleen of the Child the' cellular elements of the pulp are mainly of four 

 kinds : — Lymphoid cells, eosinophilous cells, numerous nucleated red blood-corpuscles 

 and erythroblasts, and special cells of the type of giant cells. 



The special cells are of three kinds : — ( 1 ) There is a very small number of coarsely 

 granular cells like small giant cells, their average measurement being about 20 by 

 15 fx. They have usually two or three nuclei that vary considerably in size, and may 

 or may not have vacuoles. (2) A few cells resemble those characteristic of the spleen 

 of the eight months' foetus ; most of the vacuoles contain nuclei, the empty ones are in 

 the proportion of one to three. (3) By far the most numerous are cells consisting of 

 one or two oval nuclei and many vacuoles which are surrounded by a variable amount 

 of granular protoplasm that stains somewhat deeply pink with eosine. Their usual size 

 is about 20 jjl in diameter, but they may be 30 \l in diameter, and sometimes they are 

 as large as 42 by 18 p. (Plate III. figs. 18, 19, and 20.) There may be four or five 

 small vacuoles close to a central nucleus, all being surrounded by a broad band of 

 coarsely granular protoplasm. Occasionally there are a few small vacuoles, together with 

 a long oval nucleus, in a peripheral band of protoplasm, while the middle of the cell is 

 occupied by a large vacuole that sometimes contains a round protoplasmic corpuscle 

 whose diameter is about 10 /u, and that of its nucleus about 7 /x. More frequently, 

 however, the cell contains so many vacuoles that its substance seems to consist almost 

 entirely of their apposed capsule-like walls ; there is usually in addition a single 

 almost elliptical nucleus surrounded by a little granular protoplasm at the periphery of 

 the cell. These cells occur in large numbers within the venous sinuses, and the red 

 blood-corpuscles by which they are surrounded adhere to their surface. The larger 

 cells, found especially in the pulp, have usually two oval nuclei imbedded in a small 

 amount of granular protoplasm and situated near the middle of the cell ; around them 

 are frequently seen numerous erythroblasts. (Plate III. fig. 21.) Characteristic giant 

 cells occur in some of the follicles ; they vary from about 50 by 20 fi to about a third 

 of that size. In the pulp around the follicles are similar but smaller giant cells ; they 

 have usually less protoplasm, more vacuoles, and a smaller nucleus. 



In the spleen of a Human Adult — a healthy man — the cellular elements of the pulp 

 are lymphoid cells, eosinophilous cells, and coarsely granular protoplasmic corpuscles. 

 The latter are most numerous near the follicles, while they occur in large numbers 

 within the follicles. Their average size is about 8 /a in diameter ; they have usually 

 a single round nucleus that measures about G /x, which has no nucleolus, but a well- 

 marked intranuclear network. Occasionally one of the larger cells is seen to contain a 

 large-budded nucleus. The smaller cells sometimes show ill-formed karyokinetic figures. 

 These cells thus resemble very small giant cells rather than erythroblasts. 



There were no characteristic giant cells found in this healthy spleen. 



