150 SPECIAL HISTOLOGY. 



other conclusions than those at which we have arrived. Remak 

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

 From the known facts, that other pigment cells exist than 

 those whose colouring 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 inclosed blood-corpuscles exist at all, but also, that 

 in the spleen no blood-corpuscles are destroyed, i. e. change into 

 pigment granules. This is so strong an assertion, that I see no 

 necessity for my contradicting it j 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 existence of the cells 

 in question, though he explains their origin in another 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 patho- 

 logical ? On the one hand, very weighty reasons present them- 

 selves 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 apparent continuance of 

 perfect health, notwithstanding the enormous quantity of dis- 

 integrating blood-corpuscles ; thirdly, the occurrence of blood- 

 corpuscle-holding cells in blood-vessels 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 many others, which 

 almost involuntarily lead to the idea, that perhaps all the 

 changes of the blood-corpuscles in the spleen are abnormal, 

 a view to which my observations in Fishes also tend. Here, 

 1. the metamorphoses of the blood-corpuscles in the spleen do 

 not go on in the interior of blood-vessels, but in extravasations 

 which resemble pathological aneurismata spuria (see * Mikr. 



