282 DR A. J. WHITING ON THE 



touching, each other. Occasionally the nuclei have the shape of grains of corn. 

 Near a giant cell that was apparently breaking up, a nucleus, unsurrounded by 

 hyaline protoplasm, was seen to be connected by a thread of chromatin with the 

 nuclei of the giant cell, which was still surrounded by granular protoplasm. A 

 noticeable feature of this spleen was the large amount of pink-stained granular material 

 present in the larger veins. 



In the spleen of the Puppy the cells of the pulp were mainly of three kinds : — (l) 

 Round, small, deeply stained cells, measuring 4 n in diameter, which in the pulp 

 have a very faint rim of perinuclear protoplasm, and in the veins have a distinct 

 rim. (2) Round or oval protoplasmic corpuscles, the erythroblasts, occur in numbers 

 throughout the pulp and in the veins. Their hyaline protoplasm stains deeply pink 

 with eosine, and their nucleus has no nucleolus, but an open intranuclear network. 

 The diameter of the cell varies from 7-10 m, that of the nucleus from 6-8 m. (Plate 

 II. fig. 12.) (3) The giant cells resemble closely those described in the spleen of 

 the young pig ; they show similar vacuoles and mouth-like openings. A vacuole 

 usually contains either a small deeply stained cell like the homogeneous connected 

 nuclei of the giant cells, or a protoplasmic corpuscle consisting of a large, clear, faintly 

 stained nucleus, with characteristic intranuclear network, surrounded by a rim of 

 hyaline or very finely granular protoplasm. The average measurement of the giant 

 cells was about 36 by 28 /*. Their main substance consists of coarsely granular 

 protoplasm which stained deeply pink with eosine, but at the periphery of the cell 

 there was a zone of hyaline protoplasm which varies in breadth from a sixth to a 

 third of its radius. Sometimes these two kinds of protoplasm are apparently separated 

 by a narrow circular cleft, and often the hyaline rim seems to have separated like a 

 rind from the granular core. The protoplasm of the giant cells, and also of the 

 protoplasmic corpuscles, has a distinctly yellow colour in the unstained condition, 

 similar to, but fainter than, that of the red blood-corpuscles, and both stain deeply 

 with eosine. 



Most of the small, deeply stained, apparently homogeneous nuclei, when near the 

 centre of the cell, are connected by chromatin threads, but other nuclei, always isolated 

 and usually near the periphery of the cell, are faintly stained, vesicular, and have a 

 conspicuous intranuclear network. Similar nuclei are sometimes seen in buds or large 

 bulgings of the giant cell, and occasionally such a nucleus, surrounded by a rim of 

 protoplasm, is contained, apparently within a vacuole, in the substance of the cell, and 

 seems to be of the same kind as erythroblasts surrounding the giant cell. (Plate II. 

 fig. 12.) Sometimes all the nuclei are faintly stained and vesicular, then they appear 

 to be unconnected with each other and nearly fill the cell. The giant cells sometimes 

 show indications of division by multiple karyokinesis. They are sometimes to be found 

 within the larger veins in the substance of the spleen. 



In the spleen of the Cat the reticulum of the pulp closely resembles that in the 

 dog's spleen, but the meshes seem to be slightly smaller and the cell processes somewhat 



