SPLEEN. 



force, and is eafily broken down. It appears, when divided, 

 foft and fpongy. Its colour is deeper than that of the lur- 

 face. It feems thoroughly penetrated with blood, which is 

 not coagulated, which may be fqueezed out, but does not 

 flow very readily. In lome fubjefts, more particularly 

 young ones, there is a granular appearance, arifmg from 

 numerous fmall bodies, called acini : thefe are rendered 

 more vifible by breaking the fpleen, and obferving the 

 broken iurface. If the divided furface be fcraped with a 

 knife, blood is exprelied, and fome of the parenchymatous 

 fubllance is ufually detached. If we fubjedl it to frequent 

 wafhings, the blood is difcharged from it, and the organ is 

 reduced to a loofe fpongy tiflue of whitifh fibres and 

 laminae ; many of which adhere to the internal furface of the 

 fibrous membrane. If the blood is carefully prelTed out from 

 the veffels, and they are then waiTied out by repeated in- 

 jeftions of water, the fpleen, carefully inflated and dried, 

 exhibits a mere cellular and fpongy mafs. 



This parenchyma of the fpleen confifts of the blood- 

 TefTels, ramified in the ufual way, and terminating in a ca- 

 pillary fyltem, and of certain cells, which are eafily injefted 

 from the fplenic vein with coarfe injeftion. The ramifica- 

 tions of the veins, and thefe cells, are of very delicate Itruc- 

 ture, fo that they eafily give way under injeftion. 



The cells of the fpleen were noticed by Malpighi, who 

 defcribes in the organ a number of fmall glands, hollow, and 

 furrounded by arterial zones, into which he had never been 

 able to trace any venous branches. Cuvier defcribes fmall 

 corpufcles, whofe ufe is unknown. Sir Everard Home fays, 

 in his obfervations on the itruclure and ufes of the fpleen, 

 " I have examined it after death, under the ordinary circum- 

 ftances, and have found the appearances defcribed by Cuvier. 

 1 have alfo examined it frequently immediately after the fto- 

 mach had received unufual quantities of liquids, and in that 

 ftate have found invariably that the corpufcles of Cuvier, 

 which were the glands of Malpighi, are diltinft cells, 

 containing a fluid, which efcapes when the cells are punc- 

 tured, and renders their membranous coat vifible ; fo that 

 it would appear that the diftention of thefe cells is connefled 

 with the Itatc of the llomach, and therefore only takes 

 place occafionally ; and that the elaftic capfule, by which 

 the fpleen is furrounded, adapts the organ to thefe changes 

 in its volume." Sir Everard Hates farther, that " in the 

 fpleen of the bullock, horfe, and hog, the cells, when the 

 arteries and veins are injedtcd with coloured li/.e, are feen to 

 have numerous arterial branches ramifying in their coats, 

 but no venal ones, which confirms the llatement of Mal- 

 pighi : and when the cells are empty and contraftcd, and the 

 blood-veflels filled to a great degree of minntenefs, the ap- 

 pearance of cells is entirely loil, as Itated by Cuvier. When 

 the cells were in a diltended (late, their cavities, in a great 

 many indances, were very dillinft, having been laid open in 

 making a feftion of the fplt-en. The intermediate parts of 

 the fpleen arc but fparingly fiipplied with arterial branches ; 

 and the fmaller ones ^arteries ?) do not appear to have any 

 particular dillrlbntion. When the veins only are injeftcd, 

 their branches appear more numerous, and larger than thofe 

 of the arteries, making the whole fubftance of the fpleen of 

 a red colour. They appear to arifc from the outfide of the 

 cells, going off at right angles to their circumference, like 

 radii. Where the injeflion has not been very minute, they 

 are feen to arifc at not many points of thecapliile; but 

 where the injeftion has got into fmaller branches, their num- 

 ber is lo much increafcd, that they appear to form plexufcs 

 round the cells." Phil. Tranf. i8.;B, p. 47 — 41). 



In a fecond paper on the fame fubjctf, fir Ev'-rard informs 

 »s, " that the fpleen is met with in two very different Hates, 



one of which may be termed the diflended, the other the 

 contrafted, and that in the one its fize is double what it is in 

 the other. In the diftended Hate there is a diiliuft appear- 

 ance of cells containing a limpid fluid, diftinguifhable by 

 the naked eye : in the contraded, thefe only become diftinft 

 when feen through a magnifying-glafs. The diftended ftate 

 takes place when the ftomach has received unufual quantities 

 of liquids before the animal's death ; and the contraAed 

 Hate, when the animal has been kept feveral days without 

 any drink, before the fpleen is examined." Ibid. p. 140. 



It is obferved by Haller, that in the calf, and moft other 

 herbivorous quadruped?, the llrufture of the fpleen is more 

 obvious, and eafily exhibited, than in the human fubjeft. 

 " In thefe animals, very ftrong and evident fibres and 

 laminsE arife from the external covering of the fpleen, pe- 

 netrate into the interior of the organ, are attached to the 

 coats of the blood veflels, and laftly, having decreafed in 

 fize, end in all direftions in the pulpy ftruclure of the 

 fpleen. In this way they compofe a cellular tiffue much 

 more loofe than in man. If water be thrown into the vein, 

 the organ then preffed, and thefe proceedings repeated, until 

 the fluid comes out clear, the whole may be diltended, by 

 inflation of the vein, into an appearance very much like that 

 of the lungs. From this texture, there is a very free paf- 

 fage into the vein, which feems to open by very fhort 

 brar:ches, as it were foramina, into the cellular tiffues. 

 The fibres are neither mufcular nor vafcular, but cellular ; on 

 account of their ftrength in the larger animals, fome have 

 called them ligamentous." Elem. Phyfiolog. lib. xxi. feft. I. 

 § 15. 



Heretofore great difputes exifted about the fmall bodies 

 called acini, which are obferved in the fubftance of the fpleen. 

 Malpighi, who firft noticed them, deemed them fmall hol- 

 low glands. Ruyfch infifted that they were merely the mi- 

 nute veffels an"uming a peculiar arrangement ; and that this 

 ftrufture could be demonftrated by fuccefsful injeftions. 

 The latter opinion has been gradually adopted by the bell 

 anatomifts ; among whom we may enumerate Albinus, 

 Haller, and Soemmerring. " Qui nonnunquam occurrunt, 

 acini vel glomeruli, microfcopii ope accuratiffime explorati, 

 nihil aliud funt ni fi vaforum fafciculi, vel teretes pcnicilli, 

 aut cirri vafculofi." De Corp. Hum. Fabric, t. vi. p. 157. 



The refemblance of the fpleen to glands in its ftruc- 

 ture, has led to a very careful fearch after an excretory 

 duft ; but nothing of this kind has ever been detefted ; 

 although (ucli difcoveries have heretofore been publifhed. 

 We know ot no connexion between the fpleen and anv 

 other organ, except by means of blood-vellels or nerves. 



In a paper, containing experiments on the paffage of fluids 

 from the llomach into the general circulation, &c. publilhed 

 in the Phil. Tranf. 1812, p. 51, fir Everard Home advances 

 the opinion, that a fecretion takes place into the cells of the 

 fpleen, that the fluids thus fecrcted are conveyed by the ab- 

 forbents into the thoracic duel ; and, confeqncntly, that 

 thofe veffels arc excretory dufts of the fpleen. With de- 

 ference to this ingenious and indefatigable inquirer, we may 

 fuggeft, that the faft of the fpleen pertormiug any fecretion 

 is not yet proved ; confoquently, that we need not employ 

 ourfelves in difcovering the means of conveying away inch 

 fecretion. 



The blood of the fpleen feems to be dillinguifhed by fome 

 peculiarities. It is never feen coagulated : Haller fays that he 

 never faw it in that flatc ; but according to Socnunerring, 

 a t'ue clot (polypus) has been obfervi d in the (j)lenic vein. 

 (Elem. Phyfiol. t. vi. p. 404. De Corp. Hi;m. Fab. t. vi. 

 p. 156.1 It is faid to be darker coloured than other venous 

 blood; but cxpofure to oxygen gives it the fcarlet tint. 

 9 Haller 



