660 ABSORPTION. 



experiment, in which the frog was kept only one hour in the solution, 

 the salt could not be detected in the lymph. These exceptions are 

 strikingly corroborative of the rule. Of the various salts employed, 

 only those mentioned appear to have been detected in the chyle of the 

 thoracic duct. It is, therefore, legitimately presumable, that they 

 entered adventitiously, and probably by simple mechanical imbibition: 

 the mode in which venous absorption seems to be effected. 



The property of imbibition, possessed by animal tissues, has already 

 been the subject of remark (page 65). It was then shown, that they 

 are not all equally penetrable; and that different fluids possess different 

 penetrative powers. This view is confirmed by the experiments of 

 MM. Tiedemann and Gmelin on the subject under discussion. Although 

 various substances were placed in the same part of the intestinal canal, 

 they were not all detected in the blood of the same vessels. Indigo 

 and rhubarb, for example, were found in the blood of the vena portse. 

 Camphor, musk, spirit of wine, spirit of turpentine, oil of Dippel, 

 asafoetida, garlic, not in the blood of the intestines, but in that of the 

 spleen and mesentery; prussiates of iron, lead, and potassa in that x>f 

 the veins of the mesentery ; those of potassa, iron, and baryta in that 

 of the spleen ; prussiate of potassa, and sulphates of potassa, iron, lead, 

 and baryta in that of the vena portae as well as in the urine; whilst 

 madder and camboge were found in the latter fluid only. 



Experiments by MM. Flandin and Danger 1 confirm the general rule 

 of the absorption of poisons from the digestive canal by the branches 

 of the vena portse, and the diversity of locality in which they are met 

 with. Their latest examinations were made on the absorption of the 

 salts of lead, which they detected in the digestive tube, liver, spleen, 

 kidneys, and lungs, but not in the blood, heart, brain, muscles, or 

 bones. 



The evidence in favour of the action of the chyliferous vessels being 

 restricted to the absorption of chyle, whilst the intestinal veins take 

 up other matters, is not, however, considered by some to be as incon- 

 clusive as it is by us. M. Adelon, 2 for example, concludes, that, as 

 the sectators, on both sides, employ absolutely the same arguments, 

 we are compelled to admit, that the two vascular systems are under 

 exactly similar conditions; and both, consequently, participate in the 

 function. We have seen, that whatever may be the similarity of argu- 

 ments, the facts are certainly not equal. 3 It is proper, however, to 

 remark, that chemical analysts experience great difficulty in detecting 

 inorganic substances when these are mixed with certain of the com- 

 pounds of organization; and this may account for such substances not 

 having been discovered in the thoracic duct, even when present there. 



With regard to the mode in which the absorption of fluids is effected, 

 a difference of opinion has existed, and chiefly as regards the question, 

 whether, as in the case of the chyle, any vital elaboration be con- 

 cerned, or whether the fluid, when it attains the interior of the vessel, 

 be the same as without. The arguments in favour of these different 



1 Gazette Medicale. 3 Fevr., 1844. 



2 Physiologic de I'Homme, edit, cit., iii. 111. 



3 Bollock's Physiol., 3d edit., p. 607, Lond., 1836. 



