SPLEEN. 



Itates its weight at from fix to fifteen ounces; and its 

 fpecific gravity to that of water, as 1060 to 1000. It has 

 been allerted, that the kind and the circumftances of death 

 influence the fize of the fpleen ; and we may readily be- 

 lieve that a part of fpongy texture, contammg fo much 

 blood, will be fmaller in an individual who has perifhed 

 from hsemorrhage than in one who has died of afphyxia. 

 All phyfiologills have reprefented that the fize ot the 

 fpleen is influenced by the Itate of the itomach, which they 

 conceive to aft on it in two ways. They (uppofe that 

 the full ilomach prefles the fpleen againfl; the ribs, and 

 thus mechanically forces out the contents of its cells, 

 which are expanded again as foon as this prefl'ure is re- 

 mitted. It has been aJfo imagined, that when the ttomach 

 is full of aliment, blood pafTes in larger quantity into its 

 veflels, which admit it more eafily ; while, in the empty 

 ftomach, the veflels fall into folds, and do not receive fo 

 much blood. In the former cafe, the blood which goes to 

 the ftomachic arteries is partly drawn away from the fplenic 

 veflels, which alfo admit it lefs readily, becaufe the fpleen 

 is at the fame time comprelTed : in the latter, thefe circum- 

 ftances are juft reverfed. Thefe obfervations feem purely 



that of a coagulum, with divided blood-veffels interfperfed 

 through it. 



It is fpongy, foft, and delicate in its texture, fo that it 

 can be broken down by moderate preflure with the fingers. 



The fpleen is furrounded externally by a fmooth, thin, 

 and clofely-adhering ferous membrane, derived from the 

 peritoneum. This coat is fo intimately united to the next, 

 that they cannot be feparated. The proper membrane im- 

 mediately inclofes the fpleen. Although this and the 

 former are infeparably united, we cannot doubt that fuch a 

 proper membrane exills, becaufe the covering is much thicker 

 than the peritoneum in any fituation. Juft. at the notch, 

 the peritoneum may be feparated for a (hort diftance from 

 the proper membrane. From the internal furface of thi» 

 covering, numerous fine filaments are continued into the 

 fubftance of the fpleen, where they form part of the pecu- 

 liar tiftue of the organ. The proper membrane is fo thin, 

 that its nature is not eafily afcertained : it feems, however, 

 to belong to the fibrous clafs, as it is corrugated by boiling, 

 and eafily receives depofitions of gelatine, or phofphate of 

 lime. Thickenings of the fplenic coats from this caufe are 

 very common. This membrane is fofter than thofe of the 



hypothetical ; and they prefent a mechanical folution of fibrous kind ufually are ; and it is elattic, fo as to accom. 

 vital proceft'es, which are certainly governed by other prin- modate itfelf to the varying bulk of the organ 

 ciples. Not a fingle faft is adduced as a foundation of this 



fanciful fuperftrutlure. It feems, on the contrary, that 

 there are fads fufficient to overturn it. " Numerous com- 

 parative experiments," fays Bichat, " made at diff'erent 

 points of time in the digeftive procefs, during the plenitude 

 and emptinefs of the ftomach, on animals of fimilar fize, and 

 under fimilar circumftances, have thewn, indeed, fenfible 

 variations in the volume of the fpleen, but not that inva- 

 riable coincidence, which has been afferted, between the 

 contraftion of the ftomach and the increafe of the fpleen, 

 and -vice ver/a. The oppofite relation was often noticed ; fo 

 that we could only conclude, that the differences of volume 

 were independent of the fucceffion of the digeftive pheno- 

 mena, and conrtituted permanent peculiarities of individual 

 organization. The kidney, the liver, &c. do not exhibit 

 an uniform fize in all fubjefts ; but we do not trouble our- 

 felves by endeavouring to find caufes for fuch variations. 



" Laftly, admitting that the volume of the fpleen varies 

 during life, whether thefe variations coincide or not with 

 determined ftates of the digeftive organs, it is repugnant to 

 the fpirit in which modern phyfiology contemplates the 

 phenomena of fife, to aflign the laxity of the fpleen, when 

 the ftomach is empty, as a caufe for the derivation of blood 

 from the veflels of the latter organ, or its mechanical com- 

 preflion by the diftended if omach, as a means of explaining 

 the more rapid pafl^age of the blood into the fyftem of the 

 vena portarum." Anatomie Defcriptive, t. v. p. 58. 



We cannot doubt, that, independently of difeafe, or of 

 fuch natural caufes as may produce changes in the ftate of 

 the fpleen, the volume of this organ is diff"erent in diff^erent 

 individuals. Animals of the fame fpecies and age, and under 

 circumftances in all refpefts fimilar, exhibit fuch diff'erences. 

 We frequently, too, find the ipleen after death, in the 

 human fubjeft, confiderably larger or fmaller than what 

 may be regarded as the ftandard fize, though alike in all 

 other points ; fo that the kind of death, or other accidental 

 circumftance, will not explain the difference. 



The colour of the fpleen is red or livid, or of fome tint 

 between thefe. The convex furface is often red, while the 

 edge and concavity are livid. The former colour is more 

 prevalent in young, the latter in old fubjeAs. When the 



The fpleen is remarkable from the fize of its artery, 

 which is larger in proportion to the organ than in any other 

 inilance, although no fecretion takes place. There are 

 great varieties in the number of fecondary branches, by 

 which it penetrates the notch of the fpleen. The hepatic 

 artery is rather larger than the fplenic in young iubjeCls; 

 but fmaller in the adult ; yet the liver in the latter is at 

 leaft five times larger than the fpleen. The branches of 

 the fplenic artery are faid to be very large in comparifon 

 with the trunk ; and the coats of the artery are remarkably 

 ftrong. Its refiftance, compared to that of the aorta, near 

 the emulgents, was as 1312 to looo. The fpleen has a 

 large fingle vein, vs-hich conftitutes one of the principal 

 trunks of the vena portarum. In a child of three months, 

 according to Haller, the artery meafured VoVdth of an inch, 

 the vein -r^oV'^''' • '" ^ child of eighteen months, the num- 

 bers were 13 and 19 ; at three years, 14 and 26. Ac- 

 cording to fir Everard Home, " the trunk of the fplenic 

 vein, compared with that of the artery, when both are filled 

 with wax, is found to be in the proportion of five to one in 

 its fize. This was afcertained both by an accurate mea- 

 furement of their diameters, and by weighing half an inch 

 in length of each in a very nice balance : the difproportion 

 between them is greater than between correfponding veins 

 and arteries in other parts of the body." (Phil. Tranf. 

 1807. pt. ii. p. 49.) It has no valves. Injefted fluids of 

 all kinds pafs with the greateft facility from the artery into 

 the vein. There are numerous fuperficial abforbents, be- 

 longing principally to the peritoneum : of deep-feated ab- 

 forbents, there is little known. The abforbents are eafily 

 demonftrated in the calf. If air is impelled under the 

 membrane of the fpleen, numerous knotted lymphatic trunks 

 appear, arifing from the whole furface of the vifcus, and 

 pafling with the great blood-veflels towards the recepta- 

 culum chyli. Many obfervers have noticed and defcribed 

 them in animals ; but they are not fo confpicuous in man. 

 The nerves are fmall ; they come from the coeliac plexus, 

 and form a flender fplenic plexus, furrounding the artery, 

 and entering the fpleen with its branches. If the organ, in 

 its natural ftate, poflefles any fenfibihty at all, it is very in- 

 confiderable. For further particulars on thefe points, fee 



organ is ctit, its internal colour feems to depend on the Artery, Vein, Nerve, and Absorbent 

 large quantity of blood it contains ; and nearly refembles The fubftance of the healthy fpleen readily yields to any 



force, 



