THE SPLEEN. 561 



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 meta- 

 morphoses of the blood-corpuscles in the spleen do not go on in the interior 

 of bloodvessels, but in extravasations which resemble pathological aneu- 

 rismata spuria (see "Mikr. Anat.," II. 2; and Todd's "Cyclopaedia 

 of Anatomy and Physiology," Art. Spleen, fig. 533; Ecker, "Icon. 

 Phys.," tab. vi. figs. 15, 16); 2, extravasations and metamorphoses of 

 their blood-corpuscles occur, not only in the spleen, but in other organs, 

 especially in the kidneys, where they are constant, and frequently also 

 in the liver and peritoneum. 



If to these facts we also add, that in certain animals, e. g. the Cat, 

 the Sheep, &c., the changes of the blood-corpuscles in the spleen are 

 very rarely met with furthermore, that their progress is not always 

 coincident with the stages of digestion it becomes very difficult not to 

 believe that the phenomena are abnormal, especially if we consider that 

 similar phenomena certainly not physiological, such as the small effusions 

 of blood into the lungs, bronchial glands and thyroid in Man, in the 

 lymphatic glands of the mesentery of the Pig and Rabbit, &c., are also, 

 on the one hand, almost as constant phenomena, and, on the other hand, 

 are accompanied by perfectly similar metamorphoses of the blood-corpus- 

 cles. However, in the latter cases, the quantity of the metamorphosed 

 blood-corpuscles is not to be compared to the immense number of those 

 which are constantly undergoing disintegration in the spleen ; and in 

 the second place, it is also possible that effusion of blood may occur as 

 a physiological phenomenon, as into the Graafian follicles, and during 

 menstruation and the detachment of the placenta. And although all 

 animals do not present a microscopically demonstrable disintegration of 

 the blood-corpuscles in their spleen, yet it does not follow that the pro- 

 cess may not occur and that when it can actually be demonstrated, it is 

 pathological. This much is at least certain, that congestions of blood 

 in the spleen occur in all animals, without exception; and it is almost 

 certain, that these congestions are, in Mammals, attended by extravasa- 

 tion. In these stagnations of blood, the blood-corpuscles may be disin- 

 tegrated, in some cases rapidly, in others slowly, which would constitute 

 an important difference for the observer ; it is also conceivable that they 

 and their consequences are physiological and have some great influence 

 upon life, since it is a fact, that in many animals they are constant, and 

 occur upon a very large scale. 



For the present, therefore, so long as the pathological character of 

 the phenomena in question is not conclusively demonstrated, I must 

 maintain their physiological nature and regard the disintegration of 

 blood-corpuscles in the spleen as a normal occurrence. * 



* [With respect to the " bloocl-corpuscle-holding cells," the reader will do well to consult 



36 



