Letters 189 



nor at all times, of the consistency and colour of milk ; 

 and therefore did these vessels carry chyle, they could 

 not always (which nevertheless they do) contain a white 

 fluid in their interior, but would sometimes be coloured 

 yellow, green, or of some other hue (in the same way 

 as the urine is affected, and acquires different colours 

 from eating rhubarb, asparagus, figs, &c.) ; or otherwise, 

 when large quantities of mineral water were drunk, they 

 would be deprived of almost all colour. Besides, did 

 that white matter pass from the intestines into those 

 canals, or were it attracted from the intestines, the 

 same fluid ought certainly to be discovered somewhere 

 within the intestines themselves, or in their spongy 

 tunics ; for it does not seem probable that any fluid by 

 bare and rapid percolation of the intestines could 

 assume a new nature, and be changed into milk. 

 Moreover, were the chyle only filtered through the 

 tunics of the intestines, it ought surely to retain some 

 traces of its original nature, and resemble in colour and 

 smell the fluid contained in the intestines ; it ought to 

 smell offensively at least; for whatever is contained 

 in the intestines is tinged with bile, and smells un- 

 pleasantly. Some have consequently thought that the 

 body was nourished by means of chyle raised into 

 attenuated vapour, because vapours exhaling in the 

 alembic, even from fcetid matters, often do not smell 

 amiss. 



The learned Pecquet ascribes the motion of this 

 milky fluid to respiration. For my own part, though 

 strongly tempted to do otherwise, I shall say nothing 

 upon this topic until we are agreed as to what the fluid 

 is. But were we to concede the point (which Pecquet 

 takes for granted without any sufficient reason in the 

 shape of argument), that chyle was continually trans- 

 ported by the canals in question from the intestines to 

 the subclavian veins, in which the vessels he has lately 

 discovered terminate, we should have to say that the 

 chyle before reaching the heart was mixed with the 



