itself, and the orifice by which it communicates with the subclavian vein, appear too small and narrow to suffice for the transmission of all the supplies required by the body. And I have asked myself farther, why such numbers of blood-vessels, arteries, and veins should be sent to the intestines if there were nothing to be brought back from thence? especially as these are mere membraneous parts, and on this account require a smaller supply of blood. These and other observations of the same tenor I have already made,--not as being obstinately wedded to my own opinion, but that I might find out what could reasonably be urged to the contrary by the advocates of the new views. I am ready to award the highest praise to Pecquet and others for their singular industry in searching out the truth; nor do I doubt but that many things still lie hidden in Democritus’s well that are destined to be drawn up into the light by the indefatigable diligence of coming ages. So much do I say at this time, which, I trust, with your known kindness, you will take in good part. Farewell, learned friend; live happily, and hold me always Yours, most affectionately, WILLIAM HARVEY. London, 1st February, 1654-5. LETTER VII _To the distinguished and learned John Dan. Horst, principal Physician at the Court of Hesse-Darmstadt_ MOST EXCELLENT SIR,--Advanced age, which unfits us for the investigation of novel subtleties, and the mind which inclines to repose after the fatigues of lengthened labours, prevent me from mixing myself up with the investigation of these new and difficult questions: so far am I from courting the office of umpire in this dispute! I was anxious to do you a pleasure lately, when, in reply to your request, I sent you the substance of what I had formerly written to a Parisian physician as my ideas on the lacteal veins and thoracic ducts.[59] 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. [59] [Pecquet described the duct as dividing into two branches, one for each subclavian vein.]