560 SPECIAL HISTOLOGY. 



The changes undergone by the blood in the spleen, a subject which is 

 more fully treated of in my " Mikr. Anat.," II., 2, pp. 268-270, and 

 which were observed and interpreted by 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 0. Funke also (I. c.\ who 

 are completely at one with Ecker and myself as to the facts, differ alto- 

 gether 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. fiir 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, care- 

 ful investigations, quite agrees with me ; indeed no unprejudiced obser- 

 vation can tend to other conclusions than those at which we have arrived. 

 Kemak has recently brought forward an entirely new view (I. i. c.) 

 From the known facts, that other pigment cells exist than those whose 

 coloring matter is derived from blood- corpuscles, and that effused blood 

 may form cell-like masses with blood-corpuscles, as Hasse and I have 

 more particularly shown facts which he has strengthened by new cases 

 Remak has allowed himself to be misled into asserting, not only that 

 no cells with enclosed blood-corpuscles exist at all, but also, that in the 

 spleen no blood-corpuscles are destroyed, i. e. change into pigment gra- 

 nules. This is so strong an assertion, that I see no necessity for my 

 contradicting it ; one might at last be required to demonstrate that there 

 are such things as cells and blood-corpuscles. It will interest Remak 

 to learn that Virchow, as he tells me, has satisfied himself of the ex- 

 istence of the cells in question, though he explains their origin in ano- 

 ther mode, believing that the blood-corpuscles pass from without into 

 already existing cells a supposition with which, at present, I cannot 

 exactly agree. 



An important question arises, as to the import of the changes in the 

 blood-corpuscles, whether they are physiological or pathological? On 

 the one hand, very weighty reasons present themselves for considering 

 the phenomena to be normal, particularly their constant occurrence, as 

 it may be said, in so many living animals, especially in those living 

 under natural conditions, as Amphibia and Fishes ; secondly, the appa- 

 rent continuance of perfect health, notwithstanding the enormous quan- 

 tity of disintegrating blood-corpuscles ; thirdly, the occurrence of blood- 

 corpuscle-holding cells in bloodvessels which are not cut off from the 

 general circulation, as may be demonstrated in the Amphibia ; fourthly, 

 the absence of similar, constant changes in the blood, repeated at short 

 intervals, in other organs in the higher Vertebrata ; and much more 

 might be added. To these facts, however, careful observation opposes 



