Notes, iii. 5 — 6. 203 



converted into fat, or into generative secretionsj or escapes at the extremities of the 

 vessels, forming internally the. viscera and flesh, and externally the scales, hairs, feathers, 

 etc. Cf. iii. 8, Note 2. • ' 



6. The simile is borrovfed from the Timaus {jfowett, ii. 570), and is also used at 

 /I. A. iii. 4, 15. Galen used a simile not unlike it {De Nat. Fac. iii, 15). 



7. This passage, with that quoted iii. 4, Note 20, shows clearly what was A.'^ idea 

 of the nature of flesh, or muscular tissue. He traced veins and airteries into the muscle, 

 found their branches getting smaller and smaller, until at last he lost sight of most 

 of them. This, he thought, was owing to the small veins being choked up by the thick 

 blood; the thus obstructed tubes -constituting the muscular substance. At the same time 

 the small arteries ceased to be tubular' and were solidified into tendinous fibres, which 

 being continuous on the one hand with the heart by the aorta and on the other with the 

 tendons and bones were the instruments of motion. •. . 



8. Voigtel states that he observed blood to sweat from under the arm of a young man 

 after violent exertion. Such perspiration is llso said to have been observed in scurvy 



, and low forms of fever. Landerer observed a red-coloured sweat in the axilla of a 

 patient suffering from fever. Cf. Todd^s Cycl. iv. 844. 



9. The formatioii of blood w^as supposed by A. to go on mainly in the heart, but also" 

 ■partially in the blood-vessels. Cf. De Somno, 3, 3. 



10. Cf.- ii. 4, Note 10. 



11„ If this passage be genuine, the meaning must be that the windpipe being of smaller 

 calibre than the other channels mentioned does not allow blood to flow through it so 

 easily as they do ; and. therefore that when blood gets into it, it is Qxpelled with force. 

 But I strongly suspect that the whole passage is an interpolation, written »t a later dat * 

 when oLfyrripla had. acquired the meaning of artery ; and that the passage (here without 

 meaning) had reference to the distinction between passive hoemorrhages from veins and 

 active haemorrhages from arteries. That the writer in fact mieant to say this: "The 

 veins are larger than the arteries ; and so the blood flows more easily thrgugh them than 

 through these. Thus,*when bleeding occurs from the. veins, the haemorrhage is passive, 

 as we see in the ordinary bleedings of the nose, etc.; whereas, when bleeding occurs 

 from an artery, the blood is ejected with force and the haemorrhage is active." 



12. The common iliac arteries, formed by the division of the descending aorta, do in 

 fact, as A. says, come forwards and lie in front of the common iliac v.einj ; whereas ais a 

 general rule the veins lie in front of the arteries. 



What however is meant by saying that a similar interchange of position occurs between 

 veins and arteries above the heart it is difficult to understand. I can but conjecture that 

 the reference is to the pulmonary artery (considered by A. to be a vein ; see iii. 4, Notes 

 23 — .24), wliich at its origin is in front of the aorta, and then runs upwards and backwards 

 under the aortic arch, sending, moreover its right and larger division behind the ascending 

 aorta. A" somewhat similar, but much vaguer, passage occurs in the Timceus {yowett, 

 ii- 571)- 



(Ch. 6.) 1. It will be noticed that A. always speaks oithe lung of an animal, and not 

 as we do of the lungs. H© considers the two to be merely subdivisions of a single organ, 

 because they ha.ve one common outlet, viz. the trachea. When the right and left bronchi 

 which lead from this to either lung are of more than ordinary length, as in birds, he 

 admits that the lung has the outward appearance of- being a double organ, but still 

 considers it really to be a single one for the above reason ; though " any one might think 

 that there were two because the ducts from the two divisions unite at a considerable 

 distance from them" {H. A. ii. 17, 4; D. P. iii. 7; 3). So again \H. A. i. 16, 11), 



