170 Notes, ii. 8—9. 



sensibilities have been evolved by gradual differentiations of parts, originally endowed in 

 common with the rest of the .body with sensibility to resistance and to temperature, ■ 

 both of which are included by A. under Touch ; in other words, that the remaining 

 special senses are but modifications of Touch or general sensibility. But in the treatise 

 on Sensafion (ch. 4) this view, which was held by Democritus, is expressly repudiated. 

 Touch is to A. the primary sense ; firstly, because it is the most universally distributed 

 of the senses ; no animals being without it, though they may be without any other 

 {D.A. iii. 13, 4 ; ii. 3, 8 ; H.A. i. 3, 3) ; and, secondly, because it is by touch that we 

 are able to recognise the four primary properties of matter (ii. i, Note 3; and D.A. ii. II). 

 "Touch," says John Hunter, "is the first sense, because no animal that ha.s a sense (as 

 far as I know) is without it, while there are many animals without the others." And 

 again, "Touch I call the first sense; it is the simplest mode of receiving impressions; 

 for all the other senses have this of touch in common with the peculiar or specific ; and 

 most probably there is not any part of the body, but what is, susceptible of simple feeling 

 or touch" {^Museum Cat. iii. 53, 51). 



2. This passage seems to have baffled Frantzius, and with him Mr. Lewes. Yet its 

 meaning, is clear enough, especiaiUy if one compares it with such other passages as tlrose 

 quoted in ch. 10, Note 10, The flesh, A. there argues, is not the organ of touch, in 

 the sense that the eye is the organ of sight, or the ear of hearing,, but is simply the 

 medium through which the object affects the sense-organ ; and answers therefore to 

 the transparent medium, air or water, through which the • visible object acts on the 

 eye, or to the air through which sound acts upon the ear. In the present passage A. 

 says that inasmuch as there is air or water about an animal wherever it may move itself, 

 the requisite medium for sight or for hearing is always at hand, and there is no reason 

 why nature, even if she were able, should so attach the medium of these senses to the 

 sense-organ, as to make it an actual part of the body. But, in the case of touch, a solid 

 medium is required for the action of the object upon the sense-organ, and this can 

 only be always at hand, if it be permanently attached to the organ, and carried about 

 by the animal as part of its own body. 



3. Cf. iv. 8, Note i ; as to Testacea, cf. iv. 5, Note 25. 



4. Cf. iii. 9, Note 3 ; as to Insects, cf. iv. 6, Note i ; as to Cephajopods, iv. 9, Note i. 



5. Cf.'iii. 4, Note 20. 



6. Cf. iv. 9, Note 6. 



7. Cf. Introd. p. xxix. Note i. " 

 (Ch. 9.) 1. What prevents the blood' from coagulating in the living vessels is still 



unknown ; but certainly it is not rnere heat, as A. assumes. For moderate heat really 

 favours coagulation, and a temperature about that of the body is found to' be most 

 favourable to the process (cC HausorCs tVoris, Syd. Soc. p. 4). 



2. i.e. Ball and socket joints, as of hip and shoulder. The next form, containing an 

 astragalus (cf. iv. 10, Note 44), -is the ancle joint. The third kind mentioned includes 

 arthrodial joints, e.g. the sterno-clavicular, carpal, etc., but probably refers more* 

 especially to the knee-joint with its semilunar cartilages. 



■3. So also iv. 10, 44. To these advantages derived from the absence of abdominal 

 ribs might be added the facility afforded for the motion of the diaphragm during 

 respiration. 



4. i.e. Of the truly viviparous, not the ovo-viparous such as the Selachia, whose bones 

 are cartilaginous. Cf. iv. i, Note 5. 



6. Cf. ii. 6, Notes 5 and 6. ' 



G. The bon6s of birds contain a larger proportion of inorganic matter than do those 



