COMPARATIVE HISTOLOGY AND PHYSIOLOGY OP THE SPLEEN. 293 



Commentary. 



Our more accurate knowledge of the structure of the reticulum of the splenic pulp 

 dates from 1875, when Dr Klein * published his observations on the structure of the 

 spleen. My observations are almost entirely confirmatory of his ; I am in doubt, 

 however, as to the exact nature of the cells that form it, for their character seems to me 

 to be intermediate between those of endothelial cells and flattened branched connective 

 tissue corpuscles, and rather to resemble the latter, as seen for example in tendon or in 

 the cornea, than the former. I have never seen any indication of the production of 

 lymphoid cells by budding from the cells of the matrix that he describes/I" nor the 

 presence of pigment and coloured blood-corpuscles in the cell plates ; and I cannot 

 accept his opinion that the giant cells form a part of the membranous stroma. J 



The chief interest in the study of the cellular elements of the splenic pulp seems to 

 centre around those appearances that by some observers are believed to indicate a 

 destruction, and by others a production of coloured blood-corpuscles. 



Tlie following evidence appears to me to he adverse to the theory of phagocy- 

 tosis as regards the Giant Cells : — 



(1) They occur in the spleen at the time when blood formation has been proved to 

 be taking place in it, — during late embryonic and early extra-uterine life, — just at those 

 periods when one would expect loss of blood to be most disadvantageous. Although 

 Van der Stricht § considers that they devour the extra vasated nuclei alone of erythro- 

 blasts, Denys || believes that they take up the entire erythroblasts. (2) They occur in 

 the follicles, where there are few if any coloured blood-corpuscles, and yet they do not 

 take up the lymphoid cells. Erythroblasts are, however, found in the follicles around 

 the giant cells, and in the mouth-like openings at their periphery. (3) Although the 

 giant cells contain many empty vacuoles, we have never seen any partially digested 

 nuclei in them. (4) If, as is more generally believed, the nuclei of nucleated red cells 

 are absorbed and not extruded, there can be no free nuclei for the giant cells to devour. 

 (5) Although the isolated nuclei that the giant cells contain, which are apparently 

 identical in character with those of nucleated red cells or of erythroblasts, have no 

 obvious perinuclear protoplasm of their own, as a rule, yet when near the periphery of the 

 giant cell they have often a distinct rim of hyaline protoplasm, and are, in fact, entire 

 erythroblasts. (6) The nuclei of contained erythroblasts may sometimes be seen to be 

 connected with the central nuclear heap of the giant cell by a long and slender strand 

 of chromatin. 



Summary regarding the Splenic Pulp. 



(1) The reticulum of the splenic pulp is formed by the anastomosis of the expanded 



* Klein (16), p. 368. t Klein (16), p. 369. 



% Klein (17), p. 426. § Van der Stricht (48), p. 88. 



|| Denys (24), p. 159. 



VOL. XXXVIII. PART II. (NO. 8). 2 R 



