THE SPLEEN. 149 



of the plasma of the blood, develope an envelope externally 

 and a nucleus in their interior, thus passing into round blood- 

 corpuscle-holding cells, of '0005 — F> 231 

 0-015'", containing 1 — 20 blood- ^^ ^^ 

 corpuscles ; and 2. these masses IB fl I 

 and cells, their contained blood- ^^ * ^^* 

 corpuscles gradually diminishing 

 in size and assuming a golden £^& 

 yellow, brownish-red, or black \0 

 colour, either in their entire state 

 or after breaking up into pig- 

 ment granules, change into pigment masses and pigmented 

 granule cells; and, finally, the latter, their granules gradually 

 becoming pale, pass into perfectly colourless cells. In many 

 cases the blood-corpuscles form no masses or cells, but pass 

 through the above-described stages of coloration and disintegra- 

 tion, like the others. 



[The changes undergone by the blood in the spleen, a sub- 

 ject which is more fully treated of in my ' Mikr. Anat./ II., 2, 

 pp. 268-270, and which were observed and interpreted hy 

 Ecker, at the same time and in the same manner as by myself, 

 have lately become the subject of much discussion. Gerlach, 

 SchafFner, and lately O. Funke also (I. c), who are completely 

 at one with Ecker and myself as to the facts, differ altogether 

 in their interpretation of them ; and believe that, instead of 

 their being the result of a dissolution of the blood-corpuscles, 

 they proceed from a process of development of new corpuscles, 

 and that therefore the spleen — as, indeed, was Hewson's 

 opinion — is a formative organ for blood-corpuscles. 



I have already, in another place (Zeitsch. fur wiss. Zool., 

 p. 115), confuted Gerlach's views, and I therefore consider it 

 to be unnecessary to enter, again, into this question, the less, 

 as Ecker, after repeated, careful investigations, quite agrees 

 with me; indeed no unprejudiced observation can tend to 



Fig. 231. Blood-corpuscle-holding cells and their metamorphoses, from the spleen 

 of the Rabbit, x 350 : a, two nucleated cells, with blood-corpuscles ; b f similar cells 

 metamorphosed into brown pigment cells ; c, cells from which the colour has dis- 

 appeared again ; d, pigment granules which have arisen from metamorphosed free 

 blood- corpuscles. 



