ABSORPTION FROM THE DIGESTIVE CAVITY. 199 



An important, therapeutic application of this fact is seen in the ticatment 

 of dropsies, or at least those involving the great serous cavities, where the 

 absorption of the effused serum is accelerated by drawing away a portion of 

 the fluid constituents of the blood, by the aid of diuretics and hydragogue 

 cathartics.] 



141. The difficulty which formerly existed in regard to the absorption of 

 fatty bodies into the absorbent vessels, since these traverse moist animal mem- 

 branes with great difficulty, is in some measure set, aside by the observations 

 of MM. Heidenhaiu and Briicke, already detailed, though there are still 

 some points which have not received explanation. 1 The entrance of fat- 

 molecules into the bloodvessels may be aided, as Beclard 2 supposes, by the 

 direct pressure of the muscular coats of the intestines ; for though great 

 force is requisite to drive oil through the entire thickness of the walls of the 

 small intestine, a much slighter one will suffice to impel it through the deli- 

 cute structure of the mucous membrane alone, especially if the oil be finely 

 divided or emulsionized ; the yolk of egg, for instance, mingled with two or 

 three times its weight of water, traversing such a membrane at a temp, of 100 

 F., and under a low pressure, with great ease ; though, in other experiments 

 made by M. Morin, 3 much difficulty was experienced with milk, on account of 

 the much larger size of the molecules of oil contained in that fluid. It is cer- 

 tain, moreover, that the presence of a weak solution of soda or potash in the 

 pores of the membrane, which effects a saponification of the oil, materially 

 facilitates its passage; 4 and Wistiughausen and Hoffmann 5 have observed 

 that the force requisite to drive oil through an animal membrane is materi- 

 ally diminished by first impregnating the latter with bile; an important 

 observation in reference to the phenomena of the absorption of these sub- 

 stances by the bloodvessels, since it renders it probable that, as in the case 

 of the albuminous compounds, it is in the small intestine chiefly, the surface 

 of which is rendered alkaline by its own secretion, and by the fluids dis- 

 charged by the Liver and Pancreas, that the absorption of fat is accom- 

 plished. 6 



142. It is a very remarkable fact, which has recently been fully substan- 

 tiated, that not merely soluble matters, but insoluble substances in a state 

 of minute division, may find their way from the alimentary canal and from 

 the serous cavities into the current of the circulation. Thus it was found 

 by Oesterlen, 7 that particles of finely-divided charcoal, introduced into the 



i 



1 For a very full and interesting critique upon the whole question of the absorp- 

 tion of Fats,"see Funke, Physiologic, 18C.3, 4th edit., p. 357-372. Dr. Broadbent 

 (Journal of Anatomy and Physiology. 1870, vol. iv, p. 14) has pointed out that the 

 extremely delicate layer of cells forming the walls of the roots of the lacteals and lym- 

 phatics present but little resistance to the entrance of fat-molecules. He contends 

 that these vessels may be regarded as intertextural spaces; and whilst the more dif- 

 fu.-ible substtmces, as sugar, "peptones, salts, etc., pass by osmosis through the walls of 

 the capillary bloodvessels to enter the blood, the greatly inferior diifusibilHy of the fats 

 causes them to be left behind in these intertextural spaces, from which they slowly 

 make their way into the lymphatics possessing proper walls. It must be admitted, 

 however, that the columnar cells of the intestine seem to have a special predilection 

 for, and power of, absorbing tinely divided and emulsionized fat. 



2 Physiologic, 1862, p. 181. 3 Memoires de la Societe" de Geneve, 1854. 



4 Matteucci, Lectures on the Phys. Phenom. of Living Beings, Pereira's edit., 

 p. 111. 



5 Dissert. Inaugur , Dorpat, 1861. 



6 For the best recent account of the various phenomena of imbibition, capillarity, 

 osmosis, and diffusion of liquids, see Milne Edwards, L('9ons sur la Physiologic, vol. 

 v, 1859, in which the literature of the subject is given in a singularly perfect man- 

 ner. See also Prof. Graham's Memoirs in the Phil. Trans, for 1850, 1854, 1857, etc. 



7 Heller's Archiv, 1847. 



