2IO ' Notes, iii. 9. " . • 



escaped his notice. It is true they are so differently shaped from those of a mammal, 

 or even of a tortoise, that they might appear to a careless observer to be totally different 

 organs. But the probable explanation is that A. argued h priori that it was impossible 

 for there to be a kidney ..if there were no bladder. For the essential organ in the 

 formation of urine was, as he thought, hot the kidney, but. the bladder ; and the kidneys 

 were but adjuncts to this (iii. 7, Note 18). A kidney then in an animal without a 

 bladder was to A. just as absurd a supposition as would be to us an urinary bladder 

 when there was no kidn6y. That A. was misled by this preconception is shown by the 

 fact that he did see the Icidneys in birds, and did recognize their kidney-like aspect ;* 

 but yet refused to consider them as true kidneys. 



2. In birds' the kidneys, almost always trilobed.are flattened against the back, and, 

 fitting into the deep interspaces between the bones, retain the impressions of these 

 successive cavities or depressions. • 



3. The Emys was some freshwater tortoise {^H. A. v. 33, 3) ; but what species is 

 uncertain, as there are several in Greece. None is without a bladder, but this is equally 

 true of all known Chelonia. Neither has any animal now known as Emyi a soft shell. 

 The Sphargis coriacea or leathery turtle has a soft shell, and is consequently supposed 

 by Frantzius to be the species meant. But' the Sphargis is a marine species. Possibly 

 Emys may have been a name common to both freshwater tortoises and to th5 marine . 

 Sphargis. ■ . 



4. Cf iii. 7, Note 8. • " . * 



6. The cavity in the seal's kidney is very small. It is pictured in section by Buffon 

 {^Hist. Nat.yixa.. pi. 48). The kidney consists of numerous distinct lobes, and in this 

 respect resembles that of an ox. , 



6. This is not true of adult man, excepting as an occasional anomaly. But it is true 

 of the foetus. This is one of the state'm'ents which lead me to fancy that A. may have 

 dissected the human foetus. Cf. i. 5, Note i. • 



7. Not all quadrupeds other than the ox have non-lobulated kidneys, though such is 

 the general rule. The elephant, bear, otter, all have lobulated kidneys. It is a curious 

 fact, not yet explained, that the kidneys are of. this character in nearly all water 

 Mammalia. • 



8. The bloodless ducts are the ureters. The ducts from the aorta and great vessel are 

 the renal arferies and veins • respectively. The reason why A. introduces the word 



. " continuous " appears from the last sentence in this chapter. 



9. Cf. iii. 7, Note 18, ' , ' ' ' 



10. The same fanciful nietaphor was used before. Cf. iii. 7, Note 10. 



11. This is the general but not universal rule. One of the exceptions is man, where 

 the right kidney is usually slightly lower than the left. 



12. As it was an axiom with A. that the right side .was naturally superior to the left 

 (cf ii. 2, Note 6), so also was it another axiom that all locomotion began from the right 

 {De Casio, ii. 2, 4). In fact, his definition of right is the part from which locomotion 

 begins. In the treatise De An. Incessu (4, 7; 6, i) evidence is adduced in support of this 

 axiom. That motion begins on the right is shown, it is said, by men preferentially 

 carrying bjirdens on the left shoulder, so as to leave the motor gjde free ; as also by 

 their standing on the left leg more easily than on the right, with the same object ; by 

 the attitude assumed in fighting, when the left limbs are advanced and the right kept 

 back, so as to serve for motion and defence ; and, lastly, by the fact that spiral shells 

 are dextral, that is to say, that the opening whence the motor organ is protruded is on 

 the animal's right. , 



