146 AEISTOTLE'S ANHOMCEOMEEIA 



spinal column to the hips, and then to the bladder and 

 generative organs. 



It is clear from these descriptions that Aristotle was 

 acquainted with the mesenteric arteries, but that he did not 

 know that arteries are given off almost directly from the 

 aorta to the liver and spleen, these arteries being branches 

 of the very short coeliac artery, which leaves the abdominal 

 aorta just below the diaphragm. He very clearly refers to 

 the ureters, but it is not clear what are the two strong, 

 unbranched ducts {poroi) leading from the aorta to the 

 bladder. The use of the word poroi instead oi phlehes does 

 not cause the difficulty, for Aristotle often uses that word 

 to denote blood-vessels ; the difficulty is that there do not 

 seem to be blood-vessels corresponding with those mentioned. 

 They may be the spermatic arteries, or the corresponding 

 ovarian arteries, which are long, unbranched vessels ex- 

 tending in the direction of, but not to, the bladder. They 

 can scarcely be two of the vesical arteries, which are given 

 off from the internal iliac arteries and are very much 

 branched. 



No blood-vessel, Aristotle says, passes from the great 

 blood-vessel to the uterus, but many closely crowded blood- 

 vessels extend to it from the aorta. He next says that, 

 after their bifurcation, blood-vessels extend from the aorta 

 and great blood-vessel to the groins, legs, feet, and toes. 



His statement that no blood-vessel extends from the 

 great blood-vessel to the uterus is substantially correct, for 

 many of the uterine veins lead to the internal iliac veins ; 

 some of them, however, communicate with the ovarian veins 

 which lead to the vena cava inferior. His statement about 

 the vessels extending to the uterus from the aorta needs 

 some qualification. The uterus is supplied with blood partly 

 by the uterine arteries from the internal iliac arteries, and 

 partly by the ovarian arteries which branch off from the 

 aorta and communicate with branches of the uterine 

 arteries. 

 ^ Aristotle says incorrectly that, as regards the largest 



blood-vessels and their origins, the arrangement is the same 

 in all animals with blood. In small animals, he says, the 

 blood-vessels, except the great blood-vessel, are not con- 

 spicuous, for some blood-vessels are confusedly arranged, 

 just like channels in a large quantity of mud, and some 

 animals have merely a few "fibres" instead of blood-vessels. 

 In a dissected animal, especially one killed by strangulation 



