662 OF SECRETION. 



the action of morbific causes. In the latter case, the utility of Purgative medi- 

 cines, in removing the products of decomposition, is obvious. 



IX. The. Spleen, and Supra-Renal Capsules. 



708. It remains for us to consider certain other bodies, which, from their 

 having a somewhat glandular aspect, are usually ranked among the secreting 

 organs ; but which have neither excretory ducts, nor any thing that can be 

 considered as truly glandular in their structure. Of these, the largest and 

 most important in the adult is the Spleen. 



a. This organ is essentially composed of a fibrous membrane, which constitutes its 

 exterior envelop, and which sends prolongations in all directions across its interior, so 

 as to divide it into a number of minute cavities of irregular form. According to Dr. 

 Evans, whose account of the structure of this organ is the most recent, and apparently 

 the most complete,* these splenic cells communicate freely with each other, and with the 

 Splenic Vein. They are lined by a membrane, which is continuous with that which 

 lines the splenic vein; and this membrane is so reflected upon itself, as to leave oval or 

 circular foramina, by which each cell opens into others, or into the splenic vein. The 

 cells, whose usual diameter is estimated by Dr. E. at from half to one-third of a line, are 

 generally traversed by filaments of elastic tissue, imbedded in which a small artery and 

 vein may be frequently observed; over these filaments, the lining membrane is reflected 

 in folds; and in this manner each cell is incompletely divided into two or more smaller 

 compartments. There is no direct communication between the splenic artery and the 

 interior of the cells; but its branches are distributed through the intercellular paren- 

 chyma (which will be presently described) ; and the small veins, which collect the blood 

 from the capillaries of the organ, convey it into these cavities, from which it is conveyed 

 away by the splenic vein. The cells may be readily injected from the splenic vein with 

 either air or liquid, provided they are not filled with coagulated blood ; and they are so 

 distensible, that the organ may be made to dilate to many times its original size, with 

 very little force. This is especially the case in the Spleen of the Herbivora; for the 

 Spleen of a Sheep weighing four ounces may be easily made to contain 30 ounces of 

 water. That of Man, however, is less capable of this kind of enlargement. According 

 to Dr. Evans, the cells of the spleen never contain any thing but blood ;f and he notices 

 that a frequent condition of the Human Spleen after death, which is sometimes described 

 as a morbid appearance, consists in the filling of the cells with firmly coagulated blood, 

 which gives a granular appearance to the organ. 



b.. The partitions between the cells are formed, not only by the membranes already 

 mentioned, but by the peculiar parenchyma of the Spleen ; which forms a larger part of 

 the organ in Man than in the Herbivorous Mammalia. It presents a half fluid appear- 

 ance to the eye; but when an attempt is made to tear it, considerable resistance is ex- 

 perienced, in consequence of its being intersected by what appear to be minute fibres. 

 When a small portion of it is pressed, a liquid is separated; which is that commonly 

 known as the Liquor Lienis, or Splenic blood; and which is usually described (but 

 erroneously, according to Dr. E.) as filling the cells of the Spleen. This liquid, when 

 diluted with serum and examined under the Microscope, is found to contain two kinds 

 of corpuscles, one sort being apparently^identical with ordinary blood-corpuscles, and 

 the other with the globules characteristic of the lymph and abundant in the lymphatic 

 glands. The remaining fibrous substance consists entirely of capillary blood-vessels 

 and lymphatics, with minute corpuscles, much smaller than blood-corpuscles, varying 

 in size from about l-6000th to l-7000th of an inch, of spherical form, and usually cor- 

 rugated on the surface. These lie in great numbers in the meshes of the sanguiferous 

 capillaries; and the minute lymphatics are described by Dr. E. as connected with the 

 splenic corpuscles, and apparently arising from them. Lying in the midst of the paren- 

 chyma are found a large number of bodies, of about a third of a line in diameter, which 

 are evidently in close connection with the vascular system; these have long been known 



* Lancet, April 6, 1844. 



j- " It differs in no respect from venous blood taken out of any other part of the portal 

 system. I have found it fluid or coagulated, as in other parts of the venous system ; and 

 I have frequently pulled out from the splenic vein colourless coagula. Occasionally a 

 number of globules may be distinguished in it, resembling those found in the paren- 

 chyma ; but in these cases the organ appears to have suffered injury, and these matters 

 appear to have got into the cells and vein in consequence." Loc. cit. 



