ABSORPTION. 



27 



was any direct communication between the 

 organs of digestion and the bloodvessels except 

 by means of the lacteals. For this purpose 

 they mixed with the food of an animal various 

 substances, which by their colour, odour, or 

 other sensible and physical properties, might 

 be easily detected in the fluids of the body. 

 After some time the animal was examined, and 

 the result was that unequivocal traces of the 

 substances were not unfrequeritly detected in 

 the venous blood and in the urine, while it 

 was only in a very few instances that any in- 

 dication of them could be discovered in the 

 chyle. The colouring matters employed were 

 various vegetable substances, such as gamboge, 

 madder, and rhubarb ; the odorous substances 

 were camphor, musk, assafoetida, &c. ; while, 

 in other cases, various saline bodies, such as 

 muriate of barytes, acetate of lead and of 

 mercury, and some of the prussiates, which 

 might be easily detected by chemical tests, 

 were mixed with the food. The colouring 

 matters, for the most part, were carried out 

 of the system without being received either 

 into the veins or the lacteals; the odorous 

 substances were generally detected in the 

 venous blood and in the urine, but not in 

 the chyle, while of the saline substances many 

 were found in the blood and in the urine, and 

 a very few only in the chyle.* 



The conclusion, which we are disposed to 

 regard as the fair inference, from the facts and 

 arguments that have been adduced on the 

 subject of venous absorption, is that, although 

 there are strong analogies and various patho- 

 logical considerations which would induce us 

 to confine the function of absorption to the 

 lacteals and the lymphatics, yet that the result 

 of the experiments, although not uniform, is 

 upon the whole in favour of venous absorption. 

 It only remains for us to inquire how far the 

 state and actions of the parts on which the 

 experiments were made, were so far neces- 

 sarily deranged by the process to which 

 they were subjected as to render the results 

 inapplicable to the natural condition of these 

 organs. Now this certainly appears to be the 

 case in the experiments of MM. Magendie 

 and Delille, where the poisonous substance 

 was introduced into the blood ; and the same 

 remark may probably be applied to a number 

 of pathological occurrences that have been 

 supposed to 'afford a proof of venous absorp- 

 tion, such, for example, as the case of ulcerated 

 surfaces, where pus has been detected in the 

 veins, and still more extraneous bodies, which 

 may have been either accidentally or designedly 

 inserted into the ulcerated part.f But it is 



* Ed. Med. Journ. vol. xvii. p. 455 ct seq. 

 On the absorption of foreign bodies see the early 

 experiments of Lister and Musgrave, Ph. Trans, 

 for 1683 and 1701 ; also Lowthorp's Abrid. vol. iii. 

 p. 101 . .5, and La Motte's Abrid. par. 2. ch. iv. 

 p. 75, 6' ; with Haller's sanction of their accuracy, 

 1. Phys. xxiv. 2. 3 ; see also J. Hunter, in Med. 

 Com. p. 44 et seq., and Cruickshank, ch. viii. 

 On the other hand, the experiments of M. Magendie 

 and his friends would lead us to form an opposite 

 conclusion ; Elem. t. ii. p. 168, 9. See Elliotson's 

 Physiol. p. 126. 



t See the experiments of Mr. Key, in Med. 

 Chir. Trans, vol. xviii. p. 212, 13. 



not unreasonable to suppose that in these in- 

 stances, in consequence of the erosion and 

 partial destruction of the organs, the small 

 branches of the veins will present an external 

 orifice, through which the pus or other ex- 

 traneous substance may be immediately re- 

 ceived into the sanguiferous system, nearly 

 upon the same principle as in the experiments 

 related above. 



The experiments of MM. Magendie and 

 Flandrin, the results of which were so opposite 

 to those of Hunter, do not indeed lie open to 

 the same objection ; but even here there is 

 perhaps some ground for inquiry, before we 

 implicitly adopt the conclusion that has been 

 deduced from them. The experiment, as origi- 

 nally performed by Hunter, necessarily implies 

 a degree of mechanical violence, which must 

 produce a considerable derangement of the 

 actions of the parts concerned. Acute inflamma- 

 tion of a peculiarly irritable and sensitive organ 

 must have ensued, the vessels of all descriptions 

 must have become much distended ; rupture 

 and extravasation may have been not an impro- 

 bable consequence of this inflammation and 

 distention, and, in short, a general derangement 

 both of structure and functions may have oc- 

 curred, which must prevent us from drawing 

 any positive inference respecting their natural 

 condition. 



These observations will apply with much 

 greater force to a subsequent variation of the 

 experiment, which consisted in entirely detach- 

 ing a portion of the intestine from the remainder 

 of the tube, and filling this divided portion with 

 the fluid, which, as in the former case, was 

 detected in the vein of the mesentery. This 

 arrangement was supposed to afford a still more 

 decisive proof of venous absorption than the ex- 

 periment in its original state, and if we con- 

 sider the mechanical disposition of the organ 

 only, we may admit that this would be the 

 case. But it is obvious, on the other hand, that 

 the vital actions of all the parts concerned must 

 have been much more deranged, and that, on 

 this account, we ought to be proportionally cau- 

 tious in the application of such experiments to 

 our physiological theories. 



We would venture to suggest, that the re- 

 markable discrepancy which exists between the 

 experiments of Hunter and of the French phy- 

 siologists may perhaps be reconciled, by having 

 recourse to the supposition, that in the former 

 case there was less violence used to the parts, 

 and that they were left more in their natural 

 condition; whereas M. Magendie, as we pre- 

 sume, from a desire to render the effect more 

 certain or more decisive, either produced a 

 greater degree of distention of the intestines, 

 or, in some other way, caused a greater derange- 

 ment of the parts, so as to produce a difference 

 in the results. But this idea is offered merely 

 as a conjecture, from which we do not venture 

 to deduce any of our conclusions. 



Upon the whole we feel disposed to regard 

 the experiments of MM. TiedemannandGmelin, 

 and those of an analogous kind, in which extra- 

 neous substances were found in the venous blood, 

 and in some of the secretions, when they could 

 not be detected in the chyle, as more directly 



