SPLEEN. 



777 



tains one Malpighian corpuscle, is rather too 

 little than too large. 



As regards the lower animals, it would follow 

 from my researches, that the Malpighian cor- 

 puscles occur in Mammalia in precisely the 

 same way as in Man ; at least, in more than 

 twenty genera which I have examined, I have 

 never found them to be absent. It has long 

 been known that they are very distinct in pigs, 

 sheep, oxen, goats, and so also in guinea pigs, 

 hedgehogs, and bats, &c., in whom they are 

 rather larger and more resisting than in Man ; 

 and although in the dog, cat, and rabbit, they 

 are somewhat smaller and more covered by 

 the pulp, yet they are nevertheless very dis- 

 tinct. As to Birds, Bardeleben seems to have 

 recognised the Malpighian corpuscles in swal- 

 lows, pigeons, and geese ; while I have been 

 able to verify their existence in sparrows, 

 although they are not particularly distinct. 

 80 also Ecker briefly states, that he has 

 seen them in birds ; and Oesterlen mentions 

 their occurrence in the fowl, pigeon, and in 

 many of the Raptores. Amongst the Reptilia, 

 J. Mliller has detected them in the Chelonia ; 

 while I have seen them very distinctly in the 

 anguis fragilis, in whom the corpuscles were 

 surrounded by a beautiful network of capil- 

 laries. Amongst the naked Amphibia, Oesterlen 

 states himself to have seen them here and 

 there in toads and frogs ; but in direct op- 

 position to this, I have found no trace of 

 them. Just as little have I been able to de- 

 tect them in Fishes, although 1 have examined 

 many of the fresh-water genera with this 

 especial purpose. And thus the conjecture 

 of Mliller*, that they exist in all the verte- 

 brata, although in none so distinct or so 

 easy of observation as in the vegetable-eating 

 mammals must be considered as incorrect: a 

 cirumstance which is not without consider- 

 able interest in the determination of their 

 import. 



On inquiry into the more minute structure 

 of the Malpighian corpuscles, it is exceedingly 

 necessary to regard, not only their appear- 

 ances in Man, but also in the lower animals. 

 Each Malpighian corpuscle possesses a mem- 

 brane and contents, and therefore is not a solid 

 corpuscle, but rather a vesicle. The mem- 

 brane which Malpighi beheld, was minutely 

 described for the first time by Miiller and 

 Giesker. According to the first of these ob- 

 servers it is, as previously mentioned, a pro- 

 cess of the common sheath of the vessels, 

 which either immediately continues as a ve- 

 sicular swelling of the same, or is previously 

 produced into a peduncle. Giesker rejects 

 this view, at least as regards the human sub- 

 ject, and describes in each corpuscle a pecu- 

 liar, independent, and tolerably strong mem- 

 brane, which seems to have no connection 

 with the sheaths of the vessels, but receives 

 an additional thin outer covering of white 

 fibrous tissue, in which the vessels of the cor- 

 puscle ramify, and to which they frequently 

 impart their own red colour. The ma- 



* Physiologie, i. S. 486. 



jority of later observers have unconditionally 

 adopted one or the other of these views ; only 

 a few of them, as J. Simon, Henle, Ecker, 

 and Oesterlen, having taken the trouble of 

 substantiating their truth by original inquiry. 

 Henle, Oesterlen, and J. Simon, deny the 

 existence of a special membrane. The first 

 of these observers finds that the wall of the 

 corpuscles is constituted solely of granules, 

 under which appear to be comprised struc- 

 tures resembling the morphous part of the 

 contents ; while fine bundles of white fibrous 

 tissue unite on their outer surface. Oesterlen 

 and J. Simon likewise deny the peculiar mem- 

 brane (limitary membrane), an absence which 

 the latter associates with the capacity of the 

 corpuscles to fill themselves out from the 

 capillary vessels. So also Bardeleben de- 

 scribes a membrane very indistinctly. 



On the other hand, Ecker * has assured him- 

 self of the presence of a membrane in mam- 

 mals and birds. By the application of pot- 

 ash, the masses of granules which seem to 

 constitute the wall of the corpuscle were dis- 

 solved ; and he then not only saw the rami- 

 fications of the arteries on the Malpighian cor- 

 puscle with great distinctness, but he also 

 recognised that this possesses a distinct mem- 

 branous wall, in which a network of ex- 

 ceedingly fine and well-defined stripes could 

 be detected. Although these stripes are 

 actual fibres, yet, according to Ecker, they 

 everywhere cover a structureless gland-mem- 

 brane, for the wall of the vesicle is never 

 interrupted in the structureless intervals be- 

 tween these fibres ; indeed it is possible that 

 the latter are themselves but folds of a 

 structureless membrane. Amongst the most 

 recent authors, Arnold f and Huschke { ac- 

 cept Giesker's view, and Dr. Gerlach re- 

 peats Ecker's decision. As to myself, in 

 the first place, I regard it as an incontro- 

 vertible fact, that the Malpighian corpuscles 

 possess a special membrane. If one of the 

 vesicles be isolated, and sufficiently separated 

 from the surrounding tissues, it may be seen 

 without any further preparation, especially 

 with a slight pressure (fig. 527.) ; and it be- 

 comes particularly distinct if a little dilute 

 soda or potash be applied (fig. 528.). These 

 reagents dissolve all the surrounding parts 

 of the pulp, with the exception of the ves- 

 sels, and thus leave the membrane of the 

 vesicle, although somewhat altered, yet quite 

 entire. Concerning the nature of this mem- 

 brane, I have verified the following: it is 

 colourless, transparent, about 1 to 2-1000ths 

 of a line in thickness, has everywhere two 

 contours, and here and there it exhibits con- 

 centric lines. Its structure so far corresponds 

 with that of the sheaths of the vessels with 

 which it is continuous, that it contains at 

 least white fibrous tissue and elastic fibres ; 

 but the unstriped muscular fibres which oc- 



* Der feinere Bau der Nebennieren, 1846, S. 10. 



f Anatomie, ii. S. 123. 



j Eingeweidelehre, S. 178. 



Zeitschrift fiir Eationelle Medicin, Bd. vii. 



S. 77. 



