LYMPHATIC SYSTEM, 173 



deceived by them in this matter. For the veins in dead bodies 

 being easily ruptured, whenever we see injections get from them 

 into cavities, we have reason to doubt whether these injections 

 had passed by natural passages or by laceration of the small 

 vessels ; and whoever will examine the authorities that have 

 been quoted in defence of this fact, will find that an equal 

 degree of credit has been given to experiments made with such 

 coarse materials as no experienced injector will now believe 

 could pass through such small orifices, 1 as to those injections 

 which from their subtilty leave the point more doubtful. Be- 

 sides, as we found in the former chapter, such changes are pro- 

 duced upon animal bodies by death, that membranes, which dur- 

 ing life had been so tense as to prevent transudation, after death 

 were so much altered (see Note LXXVII), that in the gall-bladder, 

 for example, they allowed the viscid bile to pass. Does it not 

 therefore become doubtful, when an anatomist injects a cavity 

 from a vein, whether (although he cause no rupture) he may 

 not separate the fibres already relaxed by death, in such a man- 

 ner as to imitate this transudation? And if one anatomist 

 has been misled when he concluded transudation took place in 

 the living body, because he found it in the dead body, so may 

 they likewise, who have concluded veins arose from cavities in 

 the living because they had been able to push injections into 

 such cavities in the dead body. It must therefore, I think, be 

 allowed that' such experiments are at the best equivocal. 



Another argument used in favour of veins arising from cavi- 

 ties, particularly from the intestines, is that some anatomists 

 have affirmed that they have seen white chyle in the blood 

 taken from the mesenteric veins. But this argument will 

 appear very inconclusive, when the reader recollects, that the 

 serum of the blood let out from the veins of the arm is some- 

 times white, which must arise from some other cause than 

 these veins absorbing chyle (LXXX). And, therefore, if that 

 appearance in the brachial veins can be otherwise accounted 



1 For example, Dr. Hales's injection of tallow, resin, and turpentine varnish ; which 

 being injected, a part of the vermilion got into, the bowels, although no greater force 

 was used than that with which the blood circulates in the living body ; but then it 

 is probable that the vessels are weaker in the dead than in the living animal. 



(LXXX.) See Note LVIII. 



