i8o Notes, ii. 14 — 16. 



equivalents, according to which excess in one part should be balanced by deficiency in 

 another. This does sometimes occur, as when animals with unusually redundant hair 

 are, as not rarely, deficiently supplied with teeth. Many instances of such an occurrence 

 in the human species are given in The Field of Feb. 14, 1874. But more commonly 

 the variations in tl»e allied parts occur in the same direction, excess or deficiency in the 

 one attending excess or deficiency in the other. Thus the well-known Julia Pastrana to 

 a monstrous excess of hair added a doubled set of teeth ; and Mr. Darwin quotes an 

 agriculturist as asserting that "pigs' with little hair on their bodies are most liable to 

 lose their tails, showing a weakness of the tegumental structure. It may be prevented 

 by crossing with a more hairy breed " {Dom. An. and Plattis, ii. 327). 



6. Cf. ii. 9, Note 9. The tail in the typical bears is remarkably short, and the body 

 usually covered with very long shaggy hair. 



6. The moisture of the brain and the heat of the blood on its surface escape, according 

 to A., by the sutures (cf. ii. 7, Note 23). As to fluidity of brain, cf. ii. 7, Note 4. 



7. The subject is discussed 'at length in D. G. v. 3. 



(Ch. 15. ) 1. The explanation and the comparison are borrowed from Xenophon {Mem. 

 i. 4, 6), who puts them into the mouth of Socrates. Somewhat similarly we have 

 "my penthouse eyebrows" in Dryden, and "his penthouse lid" in Shakespeare. 



2. Cf. ii. 14, Note 6. 

 . 3. Ci. H.A. iii. 11, 11. 



4. In truth the hypertrophy which follows an increased blood-supply is more distinctly 

 marked in the case of hair than of other parts. It is well known that long hairs are 

 developed in the hyperaemic circle round old sores, ulcers, etc. I have several times 

 seen the hair on the hypersemic ear of a young rabbit, after sectioa of the cervical 

 sympathetic, become longer than that on the opposite side. 



It will be remembered that A. was ignorant of the circulation of the blood. He 

 supposed that the blood passed from the heart to the various parts by the vessels, but 

 knew nothing of its returning. Thus when the blood reached the peripheral ends of 

 the vessels, it had to pass out in some form or other ; that which escaped internally 

 formed the viscera, that which escaped externally formed hair and the like. Thus the 

 hair was . in a certain sense an excretion (cf. ii. 3, Note 8). So also was it regarded 

 by Bacon {Nat. Hist. cent. I, sect. 58) : "Living creatures put forth (after ;;heir period 

 of growth) nothing that is young, but hair and nails, which are excrements and no parts." 

 So also Shakespeare : 



"Your bedded hair, like life in excrements, 



Start up and stand on end " (Hamlet, iii. 4). 

 Very similar is the view expressed by Sir J. Paget {Swg. Pathol. Led. z). 



5. Such purposes as the growth of feathers, scales, and the like (cf iii. 7, Note 2). 

 (Ch. 16.) 1. Cf. Tennenfs Ceylon, ii. 388. 



2. The elephant is very fond of bathing, and often frequents marshy ground. But 

 Aristotle appears to have imagined its habits of life to be much more aquatic than they 

 really are. Elsewhere however {^H. A. ix. 46, 2) it is said that the elephant lives not in 

 rivers but on their banks; and is unable to swim on account of its heavy weight. 



3. From this curious passage it would appear that the ancients were already acquainted 

 with some form of diving apparatus corresponding to the submarine helmet and tubes in 

 use at the present time. It may, however, have been some very simple instrument, such 

 as the reed, by means of which Australian natives are said to be able to swim for a 

 distance under water, so as to approach a flock of ducks without being seen. There 

 is another passage in Aristotle which shows that the diving bell also was known 



