196 ' . Notes, ill. .4. 



. 18. The probable reason why -A. supposed the right side^to be hotter than the left is 

 pointed out at ii. 2, Note 6 ; and that reason would only apply in the case of man. 



19. By the apex of the heart of fishes A. plainly means the point at the anterior 

 extremity of the organ, where the bulbus arteriosus gives off the branchial artery. 

 This however has no anatomical correspondence with the apex of the heart of other 

 vertebrates. 



A. makes a similar statement as to the position of the fish's heart elsewhere (Z^. A. ii. 

 17, 1 ; De Resp. 16, 3), and accounts for it by saying that the head in other animals is. moved 

 in a vertical plane, from above ddwnwards, whereas in fishes it has no such motion. , 

 Forwards then in a fish is in the line from tail to mouth, while in other animals it is in the 

 line from above downwards, that is from the back to the sternum. Strange as this explan- 

 ation is, it is stUl stranger when one considers .that, in order to supply it, A. had to 

 abandon his usual definition of forwards, as the direction in which sight and sense 

 generally is exercised, and to give a new and inconsistent one. 



• 20. It is important to have a clear understanding of what A. meant by vivpa. (sinews), 

 as it is one of the words which have led commentators astray. The chief passage 

 concerning the vivpa. is the following {H. A. iii. 5) : "The sinews. (j'eCpa) like the blood- 

 vessels have their origin in the heart. For in the largest of the heart's cavities (i.e. right 

 ventricle) are found sinews (i.e. chordcB ttndinece') ; and the aorta, as it is called, is a 

 sinewy blood-vessel. Its ultimate branches are indeed completely sinews. For they are 

 solid, and have the same kind of extensibility as those sinews which terminate about 

 the joints (i.e. the ligaments). The sinews how^yer do hot, like the vessels, form a 

 continuous whole. For the vessels, as in anatomical outlines, give the configuration of 

 the whole body, and this so perfectly, that in very emaciated individuals the whole bulk 

 of the frame appears to consist of one mass of small vessels ; for the very same part which 

 in fat persons is flesh is turned into small vessels when they become thin. The sinews 

 "on the other hand form no such continuous system, but are placed separately from each 

 other about the joints and bendings of the bones. For, did they form a continuous 

 whole, their continuity would be apparent inemaciated bodies. . The chief sinews are that 

 connected with the hollow of the knee, which is the part of main importance in leaping, 

 the double sinew called the tendon {Achillis ?), the Epitonus, and the shdulder sinew, 

 •which two latter are used in acts requiring great strength. Others there are without 

 name^ about the joiuts. For all the bones are connected together by sinews (i.e. 

 ligaments) at their points of contact, with the exception of the skull bones, which are 

 connected by sutures. Sinew can be split lengthways ; transversely however it cannot 

 be so split, but admits of considerable extension. The sinews are surrounded by a 

 slimy fluid, which is white and sticky {synovial Jluid?). If a sinew be cut in two, it 

 never reunites. No numbness ever occurs in a part which is "without sinews, etc." 

 From this it is quite plain that what A. meant by vivpov was sinew, ligament, and fibrous 

 tissue generally ; though it is highly probable that he confounded with these such nerves 

 as" he may have seen, owing to their white colour. In fact the last clause in the above 

 quotation shows pretty plainly that such was the case. S*till it is absuM to say as did 

 Galen, and even in modern time Milne Edwards (Lefons, iii. 5), that A. held that the 

 small arteries were , converted into nerves ! This is simply a mistranslation of vtvpov. 

 What A. meant was that they were converted into tendinous fibres, and into this error 

 he was led by his limited mieans of observation rendering it impossible for him to detect 

 the minute cavity in a small arterial branch, which is indeed reduced- to nothing by post- 

 mortem contraction. ■ 



'We have now to consider in what manner these fibrous parts came to be, in A.'s 



