376 = =©Dr. Burnett on the Blood-corpuscle-holding Cells. 
organ should be made out, that it would be only one of the old 
theories revived. But this, modern ingenuity has shown may not 
be the case; for, quite recently a theory has been advanced on 
this subject, which is unique and in no respect like any of the 
preceding. KoOlliker, the distinguished Wurtzburg professor of 
anatomy and physiology, maintains that the spleen is the blood- 
destroying organ. It is indeed a significant question in physiology 
—what becomes of all the blood-corpuscles that have been used 
in the system? We find no traces of their decay in the blood- 
vessels, and, from all the appearances in the circulation, they never 
ass away. After they have served their part as oxygen-carriers, 
where is their final resting place? Kdlliker supposes that this 
refuge is in the spleen, an organ in which they congregate, as- 
sume the form of globular masses, then crumble and are dissolved, 
passing off for a biliary or some other purpose. 
This point opens for discussion several interesting topics, chief 
among which is the modus operandi by which Kolliker thinks 
this process is accomplished. 
In order to understand this, the general relations and the inti- 
mate structure of the spleen must be briefly noticed. 
one of the Invertebrata possess this organ: but it may be said, 
in general, to be present in all the Vertebrata, for its doubtful ex- 
istence is with some of the Myxinoid fishes only, and even here 
it may well be questioned if the general rule does not hold good. 
It is evident, therefore, that the Vertebrata have relations in their 
economy on which the presence of this organ depends. This 
int, however, will be reserved for future discussion. In its 
gross aspect, the spleen appears as a red, pulpy organ, with white 
points here and there dotting its surface when its investing mem- 
brane is removed, or when its structure is exposed by an incision. 
This red, pulpy matter is composed chiefly of blood-vessels he 
in place by an intercellular or delicate parenchymatous substance 
made up of nucleated cells, and of peculiar muscular fibres which 
are of recent description. 
The white points are the Malpighian corpuscles, which consist 
of vesicles filled with granular, nucleated cells not unlike those 
found in the general parenchyma. Such is the intimate structure 
of this organ with the higher Vertebrata; but with the lower 
Vertebrata, it is much less complex, no Malpighian bodies being 
found. On the whole, the spleen is a vascular, parenchymatous 
organ, composed so largely of blood-vessels that it has much varla- 
bility of size in the same individual according to the flaccidity oF 
turgidity of these vessels. We will now proceed to the poin 
at issue in Kolliker’s theory of the function of this o 
In the splenic tissue of many animals, there are not unfrequently 
observed roundish or oval masses of a brownish color, and © 
Size varying from ;j, to ;;';5 of an inch in diameter. 
