2,66 CHANGES OF BLOOD IN THE SPLEEN. [sect. 168. 



brata becoming roundish. These heaps either remain in this con- 

 dition, or go on to form cells. These cells result from the adhesion 

 of the corpuscles by a sort of plasma, followed by the development 

 of a nucleus in the interior of the heap, and of an outer envelope 

 around it. The cells thus produced are spherical, from o"005'" to 

 croi5"' in diameter, with one to twenty blood-corpuscles in their 

 interior. 2. The next step is, that these collections and cells 

 metamorphose themselves into pigment collections and pigment- 

 granule cells. The blood-corpuscles become smaller and smaller, 

 assuming a golden yellow, brown, or black colour, and become 

 pigment granules either directly or after disintegration. The 

 pigment-granule cells then undergo further change, the contained 

 granules becoming paler and paler, until all colour is lost. In 

 many cases, the blood-corpuscles do not form collections and cells, 

 although they go through the same change of colour and the same 

 disintegration as the others. 



The red pulp of Dew-born and young mammalians contains, according to my 

 observations, some interesting elements, viz., large cells with many nuclei, 

 and small yellowish nucleated cells. The latter are undoubtedly nothing else 

 than blood-corpuscles in process of formation, whilst the larger cells are also 

 found in the blood of the splenic vein and of the vessels of the liver. 



The changes of the blood in the spleen, first indicated by Ecker and myself, 

 have since been the subject of repeated examination. Some observers, as 

 Gerlach and Schaffner, regard the process as a redintegration of the blood- 

 corpuscles. Others have even denied the existence of blood-containing cells, 

 and contend that red blood-cells disappear in the sploen and become changed 

 into pigment granules. My statements are confirmed in almost every par- 

 ticular by the later researches of Virchow, who considers, however, that the 

 blood-corpuscles enter into the cells that contain them, subsequently to the 

 formation of the outer cell. 



It is an important question, whether the alterations of the blood-corpuscles 

 in the spleen are to be regarded as physiological or as pathological processes. 

 On the one hand, weighty reasons may be urged for considering them as 

 normal ; reasons derived from their constancy in the animal series, from the 

 occurrence of similar cells containing blood-discs in the general circulation 

 of amphibia, and from the circumstance that, in the higher vertebrata, these 

 changes are observed with the same constancy in no organ besides the spleen. . 

 On the other hand, there are many and still stronger reasons for believing 

 that these changes in the blood- corpuscles are abnormal only. In the first 

 place, my investigations among fishes show, that these metamorphoses are 

 not confined to the spleen, but are met with in the liver and in the peri- 

 toneum ; in the fish's spleen the changes occur within the vesicles (described 

 in the preceding section), which look like the false aneurisms of pathologists 

 (see my Micros. Anal, ii., 2, and Todd's Cyclop, of Anat., art. Spleen, fig. 533; 

 also Ecker, Icon. Phys., plate vi., figs. 15, 16). Then, again, certain animals, 

 as the cat and sheep, rarely exhibit these changes of the blood-corpuscles in 



