200 OF ABSORPTION AND SANGUIFICATION. 



alimentary caual, could be distinguished in the blood of the mesenteric 

 veins; and similar results were obtained by Eberhard, and by Mensouides 

 and Donders, 1 not only with charcoal, but also with sulphur and even with 

 starch, the latter substance being at once detectible in the blood by the 

 iodine-test. There can be little doubt that such substances enter the lacteal 

 system through the epithelial cells of the villi ; as the presence of psoro- 

 sperms in the interior of these has been distinctly perceived by Klebs.' 2 In 

 like manner, Ludwig and others in the Physiological School of Leipsic 3 have 

 noticed the penetration of particles of coloring matters from the interior of 

 the abdominal or thoracic cavities into the lymphatics of the central ten- 

 don of the diaphragm, and into those of the pleura respectively; Auspi-tz 4 

 describes a similar absorption of starch-corpuscles from the peritoneal cavity, 

 and it seems probable that this is effected through certain openings (stomata) 

 first noticed by Oedmaunson, 5 and since fully described by Klein and others, 

 which occupy interspaces between the ordinary tessellated epithelium-cells 

 lining the serous cavities. These openings, therefore, establish a direct com- 

 munication between the serous cavities and the lymphatic vessels, and the 

 cavities themselves may reasonably be regarded, in one sense, as merely 

 colossal dilatations of the vessels, analogous to those large lymph-sacs* or 

 reservoirs which are found in the frog, fish, and other animals. 6 



2. Absorption from the Body in general. 



143. The Mucous Membrane of the alimentary canal is by no means the 

 only channel through which nutritive or other substances may be introduced 

 into the circulating apparatus from external sources. The Lymphatic sys- 

 tem is present in all animals which have a lacteal system ; and the two, as 

 already pointed out, evidently constitute one set of vessels. The Lymphatics, 

 however, instead of commencing on the intestinal walls, are distributed 

 through most of the vascular tissues of the body, and especially in the Skin; 

 but their number bears no proportion whatever to the vascularity of the 

 several tissues, or to the amount of interstitial change which these undergo ; 

 and it would rather seem to be related to the amount of Connective tissue 

 interposed between the other constituents of the fabric. Thus we find the 

 Nervous centres entirely destitute of them, unless indeed they are represented 

 by the lacuuar spaces filled with nuclei, which have been described by Robin 7 

 and His 8 as surrounding the capillaries; and they are very scanty in the 

 substance of Muscles. After passing, like the lacteals, through a series of 

 glandular bodies (the precise nature of which will be presently considered), 

 they empty their contents into the same receptacle with the lacteals; and 

 the mingled products of both pass into the Sauguiferous system. We find 



1 Nederlandsc-h Lancet, Band iv. 



2 For further information on tliis point the reader is referred to Molesehott's Un- 

 lersuelmn^en, P,d. ii, p. 119; and Wien Med. Worhensclirit't, 18">4, p. S17; Hol- 

 lander, (Jua'stiones de Corp. solid, e tract, intcst., ete., Dorpitt, 18">l>; Teichmann, 

 Das Sau^-ader System, 18(il, p. 106; Funke, Lehrbueli, IN',:;, -1th edit , p. ;!ii'J et. seq ; 

 anil Kli-lis, in Arch, f Path. Anat., Hd. xvi, p. 188; and especially to Auspitz, Ks.-ay 

 in the \Vien. Mud. Jahrb., N. F., 1871, p. 283, in which the history of the subject is 

 fully ^iven. 



* See the several papers hy Lndwii^, ScJiweit^er-Siedel, Dogiel, and Dvbkowsky 

 in tin- Verliand. d. Saehs. Q-esell. d. \Viss , ISlid. 

 Wien Med. Jahr., N. F., 1871, p. 583. 

 ; Yircli.twV Arcliiv, Hd. xxviii, p :>(il. 

 r> Si'e .M . .lourdain, Ann. des Sci. Nat., 18f>7. 

 r Hro\vn-S<''c|iianl, .Journal de la 1'hvsiol., vol. ii, 1850, p. 587. 

 8 Zcits. f. wiss. Zoologie, 1805, p. 127. 



