206 OF ABSORPTION AND SANGUIFICATION. 



pbatics end in processes like the finger of a glove, which, however, are prob- 

 ably connected laterally with irregular passages, containing stellate cells, 

 through which the fluids absorbed gain entrance into their interior. In other 

 parts of the body, as in fibrous and tendinous tissues, in membranes and 

 fasciae, a peculiar system of branched cavities is almost always visible when 

 proper methods of preparation and observation are adopted. Each of the 

 cavities contains a nucleated mass of protoplasm, which completely fills it ; 

 and both the cavities and their contents are in continuity with each other, 

 so as to form a network which is now known under the name of lymph-cana- 

 licular system, 1 and the more or less branched cells contained in them are 

 termed lymphatic cells. 2 The large cavities and vessels with which the lymph- 

 canaliculi communicate appear to be always lined, whilst their walls are 

 sometimes exclusively formed by a delicate layer of flattened epithelial cells. 3 

 An external membrane is in the latter case gradually acquired, as the ves- 

 sels become larger, on which again is superimposed a layer of dense connec- 

 tive tissue, in which a few transverse muscular fibres may be distinguished. 

 It is a peculiarity of the Lymphatics that they do not present the same 

 smooth and regular contour, nor the same definite mode of branching, that 

 is met with in the Bloodvessels ; on the contrary, they run irregularly, and 

 the walls of the vessels often present dilatations or reservoirs in their course, 

 whilst the larger vessels formed by the reunion of several smaller ones, often 

 again subdivide and reunite. The principal communication between the 

 lymphatics and the bloodvessels is at the point where the great trunks empty 

 themselves into the junction of the subclavian and jugular veins. It is not 

 improbable, however, that in certain regions, as the cornea, the lymphatic 

 canaliculi form channels by which the fluid parts of the blood, without its 

 morphological constituents, can enter the rootlets of the lymphatic system.'* 

 In many parts, especially in the central parts of the nervous system, the 

 bloodvessels run in the iuterior of the lymphatic vessels, which form, as it 

 were, an additional sheath to them, the space between the wall of the lym- 

 phatic vessel and that of the bloodvessel being occupied with fluid contain- 

 ing lymph-corpuscles. At certain parts of the body, as the bend of the 

 knee and elbow, and in the neck, the larger stems suddenly break up into 

 a dense interlacing network of capillary vessels, most distinct in young sub- 

 jects, forming a rete mirabile, as is shown in Fig. 84. This is surrounded 

 by condensed connective tissue, and is penetrated by bloodvessels, constitut- 

 ing, so to speak, the first towards the formation of a lymphatic gland. From 

 this simple structure we can readily ascend through a series of glandlike 

 organs, gradually increasing in complexity, composed of several of these 

 little retia, arranged either continuously or in groups, until at length, by 

 steps of easy transition, we arrive at the complex structui'e of the true lym- 

 phatic glands. 



The details of the structure of the lymphatic glands have been most la- 

 boriously investigated and excellently described by His, 5 Kolliker, 6 Teich- 



1 Saftcamilchen of Recklinghausen. 



2 See Klein, in Handbook for the Physiological Laboratory, 1873, p. 114; also 

 Teiehmann, Das Saugader System; BelajeiF, Journal de 1'Anat., t. iii, pp. 465 and 

 594; Ludwig, in the Mcdizinischer Jahrbiieher of A. Duehek and A. Sehauenstein, 

 18G3, Heft ix, pp. 35-77, Wien ; Giannuzzi, Bcr. d. S. G. 'sells, zu Leipzig, Nov. 

 1805; 'Wywodzoff on the Lungs, Wien. Mcd. Jahrb., Bd. xi, Heft iii; Genersieh, in 

 Ludwig's'Arbeiten, H. v, 1871, p. 53. 



3 Auerbaeh, Kiilliker's Zeitschrift, Bd. xv, 1808, p. 172. 



4 See Dr. T. A. Carter, Journal of Anatomy and Physiology, 1870, vol. iv, p. 07. 

 6 Untersuchungen iiber den Bau der Peyerschen Driisen, Leipzig, 18(>2. 



6 Gewebelehre, 1866. 



