614 LETTERS. 



thoracic ducts. 1 Not, indeed, that I was certain of the opinion 

 then delivered, but that I might place these objections such 

 as they were before those who fancy that when they have made 

 a certain progress in discovery all is revealed by them. 



With reference to your letters in reply, however, and in so 

 far as the collection* of milky fluid in the vessels of Aselli is 

 concerned, I have not ascribed it to accident, and as if there 

 were not certain assignable causes for its existence ; but I have 

 denied that it was found at all times in all animals, as the 

 constant tenor of nutrition would seem to require. Nor is it 

 requisite that a matter, already thin and much diluted, and 

 which is to become fat after the ulterior concoction, should 

 concrete in the dead animal. The instance of pus, I have 

 adduced only incidentally and collaterally. The hinge upon 

 which our whole discussion turns is the assumption that the 

 fluid contained in the lacteal vessels of Aselli is chyle. This 

 position I certainly do not think you demonstrate satisfactorily, 

 when you say that chyle must be educed from the intestines, 

 and that it can by no means be carried off by the arteries, 

 veins, or nerves ; and thence conclude that this function must 

 be performed by the lacteals. I, however, can see no reason 

 wherefore the innumerable veins which traverse the intestines 

 at every point, and return to the heart the blood which they 

 have received from the arteries, should not, at the same time, 

 also suck up the chyle which penetrates the parts, and so 

 transmit it to the heart ; and this the rather, as it seems pro- 

 bable that some chyle passes immediately from the stomach 

 before its contents have escaped into the intestines, (or how 

 account for the rapid recovery of the spirits afrd strength in cases 

 of fainting ?) although no lacteals are distributed to the stomach. 

 With regard to the letter which you inform me you have 

 addressed to Bartholin, I do not doubt of his replying to you 

 as you desire ; nor is there any occasion wherefore I should 

 trouble you farther on that topic. I only say (keeping silence 

 as to any other channels), that the nutritive juice might, be 

 as readily transported by fche uterine arteries, and distilled 

 into the uterus, as watery fluid is carried by the emulgent arteries 



1 [Pecquet described the duct as dividing into two branches, one for each sub- 

 clavian vein. ED.] 



