Notes, i. 3 — 5. 149 



excepting in matters of degree ; such species together constitute a larger natural group 

 (yeVoy), still as a rule with a popular name. Some species, however, as man, stand 

 isolated, and cannot be so combined with other species (see next chapter). 



e. These larger natural groups, and these isolated species, may be arranged in still 

 larger groups. But the basis of such arrangement will be merely analogy or distant 

 resemblances of the parts, not identity with differences of degree. And such groups will 

 have no popular names (see next chapter). 



f. The natural groups may be arranged in a linear series according to the degree of 

 animality they possess ; the series extending from those animals which most nearly 

 resemble plants to those which, as man, are most remote from them. Cf. iv. 10, Note 12. 



(Oh. 4.) 1. The similarity is in the media in which the two live, the fish in the liquid 

 water, the bird in the liquid air. So in the Sophistes {Jrweti's Transl. ii. 479) we read : 

 " Of swimming animals one class live on the wing and another in the water." The close 

 resemblance of flight to natation is shown in the fact that there are both birds and insects 

 that use their wings for swimming, while on the other hand there are fishes that can 

 support themselves for a short time in the air. 



(Ch. 5.) 1. This passage seems to imply that A. had, in some degree at any rate, 

 studied the flesh, bones, and vessels, of the human body. But it does not necessarily imply 

 that he had dissected them. For his observation may have been limited to such parts as 

 were exposed in operations by the surgeon's knife, or in wounds received accidentally or 

 in battle. When in fact we remember how excessively strong was the religious feeling of 

 the Greeks as to the sanctity of the human body, and when we also See how ignorant A. 

 was of its internal anatomy, an ignorance he fully admits {H. A. i. 16, l), and which is 

 betrayed in numerous statements, we may feel certain that his scalpel had never touched 

 a human subject, or at any rate an adult one. For I am by no means so certain that A. 

 may not have sought to gratify his curiosity by dissection of the human foetus. In the 

 .first place it is quite easy to conceive that the religious feeling which peremptorily forbad 

 all meddling with the body of the adult may have disregarded the aborted embryo ; and 

 in fact there is some reason to believe [Cuvier, Hist, d. Sc. Nat. i. 39) that in the time of 

 Galen, when the religious obstacle was as strong as in the time of Aristotle, some such 

 distinction between the sanctity of adult and foetus was actually recognised. Secondly, 

 such a supposition would explain several difficulties. Thus A. says that the heart is 

 visible in the aborted embryo while it is still quite small {D. P. iii. 4, 2). He does not 

 actually say in the human abortion; but, seeing that he was able to procure the embryos 

 of other animals without waiting for the occasional accident of abortion, and in fact did 

 procure them (Z>. G. iv, i, 10 : v. i, 12), it is most natural to suppose that it is of the 

 human embryo that he is speaking. Again he says that the human kidney is lobulated, 

 like that of the ox ; and this is true of the foetus, not of the adult. Again he says that 

 the heart in man lies diagonally, with the point inclined to the left, and the right ventricle 

 above the rest (iii. 4, Note 17). It is difficult to see how he can have known this without 

 inspection. That in man there is often, though not invariably, no gall-bladder, is, again, 

 a statement which we can understand, if founded on examination of embryos. For the 

 gall-bladder is not developed till the liver is already so large as almost to fill the abdomen. 

 If, again, the description of the heart and vessels (iii. 4, Note 23) be intended for those 

 parts in man, as would seem to follow from the statement that the right ventricle is upper- 

 most, tlien this description can only have been got by examination of tiie foetus, for it 

 includes, as I believe, the ductus arteriosus. The brain, again, in an aborted foetus would 

 almost certainly be found in a diffluent condition ; and thus would be explained the state- 

 ment (ii. 7, Note 4) that the human brain is more fluid than that of any other animal. 



