• Notes, iii.- 7. 207 



2. On the question of the bilateral symmetry of the organs, and especially of the 

 abdominal organs, where alone there is any difficulty, cf. Sylvester, Disc, of Nature of 

 Spleen, p. 12, 

 . 3. Cf. iii. 6, Note i, ' 



4. By animals that necessarily have a spleen are meant, as will presently appear, , the 

 viviparous quadrupeds, or mammals ; by those that have it merely " by way of token " 

 are meant the oviparous vertebrates, i.e. birds, reptiles, amphibia and fishes.' The spleen 

 is in fact notably larger in the former than in the latter. 



There is some foundation for the statement that the size of the spleen and the distinct- 

 ness with which the liver is divided into lobes are inversely related to each other. Thus 

 it is in Mammalia that the spleen is largest in proportion to the body, and in them also 

 that the liver is least distinctly lobulated. Among Mammalia it is the rodents that have 

 the smallest spleen, and in these also it is that the liver reaches its maximum' of sub- 

 division. On the other hand, the splfcen is large in ruminants and their liver at the same 

 time presents scarcely any marks of lobulation. In the Ovipara the spleen is ijnuch 

 smaller than in Mammalia, and the liver, as a general though not universal rule, is much 

 more decidedly cleft into distinct 'lobes. . In all birds, in all batrachians, and in all reptiles, 

 excepting Ophidia, the liver is distinctly divided into two lobes. In the remaining class, 

 fishes, the spleen varies much in size ; sometimes is apparently altogether absent, some - 

 times, excessively gmall, sometimes almost as large in proportion to the body as thaf of a 

 mammal, and the liver is sometimes multilobed, sometimes bilobed, sometimes unilobed. 

 In this class, however, I cannot ascertain that there is any such relation as that mentioned 

 in the text between the two conditions. 



6. The exceptional ovipara are the Ophidia and many osseous fishes, where the liver is 

 unilobed. The exceptional vivipara are the rodents (see last Note), of which A. specially 

 mentions the hare. "Near the lake Bolbe, and in other parts, a species of hare is 

 found, that might be taken to have two livers, because the ducts unite at a consider- 

 ably distance from the organ, just as is the case with [the bronchi from the two divisions 

 of].the bird's lung" (ZT. ^. ii. 17, 4). \ ' 



6; In cartilaginous fishes th# liver consists of two distinct lobes, whereas in osseous 

 fishes it is ofteh unilobed. 



7. Cf. iii. 5, Note' 4. 



8. Assisting them va the mechanical way immediately mentioned, and also by providing 

 an outlet for their surplus blood. Cf. iii. 13, Note i ; iii. 8, Note 2. 



9. The mesentery is meant. " ■ " 



10. What I have translated "immoveably" is literally "like nails." The introduction 

 of nails into the" metaphor is however so out of place, that I am strongly tempted to 

 suggest that A. wrote ^vvi.i not ^\oi. Y.yvi.t are the large round stones to which anchor- 

 lines were fastened in old times. The metaphor would th'en run onfall fours. . The ship 

 is the main blood-vessel ; the anchor-lines are the putstretching branches ; the round 

 anchor-stories are the rounded liver, spleen, kidneys. 



11. The hepatic and splenic arteries seem to have escaped A.'s notice ; probably because 

 they are not given off directly from ihe aorta. 



12. Plato described the spleen as made of bloodless substance. Cf. yowett's. Trans. 

 ii. 566. ^ • 



■ 13. Cf. Note 18. 

 14. The spleen is small in all birdsj but whether specially so in these, or in'the owl, 

 which he adds elsewhere ^H. A. ii. 15, 7) to the list, I -cannot say. The stomach, argues 

 A., is so hot in these birds as to be able to concoct food, without the aid of a spleen. 



