518 OF ABSORPTION AND SANGUIFICATION. 



with the cells found floating in the Chyle.* Their purpose will be considered 

 hereafter. 



683. To the class of Vascular Glands belong the Spleen, the Thymus 

 and Thyroid Glands, and the supra-Renal Capsules. With the exception of 

 the first, they all have their origin (as recently ascertained by Mr. J. Good- 

 sirt) in involuted portions of the Germinal membrane; and, at an early period 

 of embryonic life, they are in actual continuity with each other. Their original 

 identity of function, therefore, cannot be doubted; and the probability of the 

 inference, which rests on other grounds, that this function is to assimilate or 

 elaborate the nutrient materials (in the manner in which the cells of the 

 leaves of Plants prepare their elaborated sap), is strengthened by its exact 

 conformity with the original function of the Germinal membrane. But there 

 is no improbability that they may severally have some subsidiary or supple- 

 mentary function to perform ; varying according to their respective structure, 

 position, and connections. This seems peculiarly the case in regard to the 

 Spleen; the origin of which body is not the same with that of the other three. 



a. According to the account of Dr. Julian Evans,J whose researches appear to have been 

 more successful than those of any other Anatomist, the Spleen essentially consists of a fibrous 

 membrane, which constitutes its exterior envelope, and which sends prolongations in all 

 directions across its interior, so as to divide it into a number of minute cavities or lacunae 

 of irregular form. These Splenic lacuna communicate freely with each other, and with 

 the Splenic vein; and they are lined by a continuation of the lining membrane of the latter, 

 which is so reflected upon itself, as to leave oval or circular foramina, by which each lacuna 

 opens into others, or into the splenic vein. The lacunae, whose usual diameter is estimated 

 by Dr. Evans 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 lacuna 

 is incompletely divided into two or more smaller compartments. There is no direct com- 

 munication between the splenic artery and the interior of the lacuna- ; but its branches are 

 distributed through the intercellular parenchyma (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 lacuna? 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 4 ounces, may be easily made to con- 

 tain 30 ounces of water. That of Man, however, is less capable of this kind of enlargement. 

 According to Dr. Evans, the lacunae of the spleen never contain anything but blood ; 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 lacunas with firmly-coagulated 

 blood, which gives a granular appearance to the organ. 



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

 mentioned, but by the peculiar parenchyma of the Spleen; which constitutes 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 expe- 

 rienced 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 lacunio of the Spleen. This liquid, when diluted with scrum and 

 examined under the Microscope, is found to contain two kinds of corpuscles, one M>rt being 

 apparently identical with ordinary blood-corpuscles and the other with the globules cha- 



* See Mr. J. Goodsir's Anatomical and Pathological Researches, p. 4G. 



f Proceedings of the 1 loyal Society, 18-16. 



t Lancet, April C>, 1844. 



"It dill'ers in no respect from venous blood taken out of any other part of the portal 

 system. 1 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 parenchyma; 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. 



