THE SPLEEN. 555 



Malpighian corpuscles have been discovered in all the Mammalia 

 which have hitherto been examined, and also occur in Birds. Among 

 the scaly Amphibia they were found by Job. Miiller in one of the 

 Chdonia, and by myself in the Blindworm, where the corpuscles were 

 surrounded by an exceedingly elegant network of capillaries. In 

 Frogs and Toads they are, according to Oesterlen, to be met with now 

 and then ; but I have not yet succeeded in finding any trace of them 

 in the naked Amphibia, nor in the fresh-water fishes. Leydig, how- 

 ever, has observed them in the Plagiostomata (Beitrage zur Anat. 

 der Rochen und Haie). Job. Muller's supposition that the Mal- 

 pighian corpuscles exist in all Vertebrata, is, therefore, not borne out, 

 a fact which is not without weight in considering their physiological 

 import. In a few Mammals the Malpighian corpuscles contain, though 

 not constantly, the same forms of retrograding blood corpuscles as 

 will be described to occur in the pulp, in the following section.* 



granules, and are filled with a homogeneous mass, consisting of soft concentrically lami- 

 nated bodies. These bodies, which were formerly regarded as colloid, have recently been 

 found by Virchow (Archiv, f. Path. Anat. VI. 2) to be the result of a cellulose metamorphosis, 

 for a watery solution of iodine, and the subsequent addition of sulphuric acid caused them to 

 assume the peculiar violet color which is known to belong to vegetable cellulose. DaC.] 



* [The Malpighian follicles of the spleen present three points of importance to the inves- 

 tigator. 1. Whether they have a capsule, and what is its nature? 2. The arrangement of 

 their vessels. 3. The structure of the substance which they contain. 



1. The capsule and its nature. We have been quite unable to convince ourselves of the 

 existence of any such capsule as that described by Professor Ko'lliker, in the Malpighian 

 follicles of Man, the Sheep, the Pig, the Cat (Kitten), or the Rat; in all of which we have 

 made very careful investigations with regard to this point. In Man, in the Pig, and in the 

 Cat, we are unable to distinguish any boundary at all between the follicles and the sur- 

 rounding red pulp the substance of the one appearing to pass into the other. At the line 

 of transition, however, the indifferent tissue of the follicle underwent a partial metamor- 

 phosis and broke up, when teased out, into spindle-shaped bodies, containing " nuclei/' or 

 short delicate fibres with " nuclei," exactly resembling, in Man, the structures described by 

 Professor Ko'lliker as peculiar fibres, and represented in Fig. 227. 



In the Rat, this border zone of metamorphosed tissue was somewhat broader and firmer, 

 and when the follicle was compressed, appeared, particularly under a low power, like an 

 indistinctly fibrous coat, such as Professor Ko'lliker describes ; but when closely examined, 

 it was readily seen to be no distinct closed capsule, but to pass gradually, on the one hand, 

 into the pulp, and, on the other, into the contents of the follicle. The same is true of the 

 Malpighian follicles of the Sheep, where the appearance of a capsule, under a low power, 

 is often very distinct ; and where imperfect elastic fibres may be met with in it. 



In fact, our own observations are perfectly in agreement with those of Mr. Wharton 

 Jones (British and Foreign Med. Review, Jan., 1853), and have led us completely to the 

 opinion of Remak- (Ueber runde Blut-gerinnsel und iiber Pigment Kugelhaltige Zellen, 

 Muller's "Archiv," 1852), that the capsules of the follicles are by no means their essential 

 element, and that we must consider the spleen to be formed by two principal constituents; 

 the first being the parenchyma, and the second a superadded fabric of bloodvessels, nerves, 

 lymphatics, elastic and contractile elements. The manner in which the latter are arranged 

 in and about the parenchyma is, in a manner, accidental and very variable. It may be, as 

 Remak says, either inter capillary, as in the pulp ; or vaginal, as in the sheaths of the arte- 

 ries ; or encysted, as at the angles of division of the arteries, in the Malpighian follicles of 

 the Sheep. 



To insist, therefore, upon the fbllicular arrangement of the spleen, or indeed of any other 



