I.] GENERAL VIEW. 9 



of man's structure, already noted, in relation to the other 

 forms of life here enumerated. 



In that man's body is bounded by curved lines and sur- 

 faces, and its structure complex, so that upon a section being 

 made it is seen to consist of different parts it agrees with 

 those of all other animals, as even in Protogenes there are 

 granules. Thus it differs from inorganic substances, which 

 may be, as in crystals, bounded by right lines, flat surfaces, 

 and have a homogeneous section a cut crystal being the 

 same in structure throughout. Only very rarely (as in 

 spathic iron and dolomite) are minerals bounded by curved 

 lines and surfaces. 



The presence of much water is also a common character of 

 organic living bodies, though man may be called solid in 

 comparison with some animals, more than 99 per cent, of water 

 entering into the total composition of a jelly-fish. 



As to his chemical composition, man agrees with the whole 

 animal kingdom, and differs from the members of the vege- 

 table kingdom in the less proportion of non-nitrogenous parts 

 which help to compose his body. 



12. I n so far as man's body is furnished with a distinct head, 

 he agrees not only with other vertebrates 



(with one exception the lancelet, or 

 Amphioxus), but also with the higher 



Mollusca and Annulosa. It is a cha- FlG THE LANCELET 

 racter, however, quite wanting in the (Ampkioxns). 



lower sub-kingdoms, and' even so- well- 

 organized an animal as the oyster is quite destitute of any 

 such part. 



The presence of limbs is not a universal character even in 

 man's own primary division, the Vertebrata, being wanting, 

 e.g., in serpents ; but the possession of more than four is 

 known only in the Annulosa r where, however, the number 

 may be not merely six, as in insects, but prodigious, as in 

 the millepedes,, or thousand-legs. 



13. The contrast between dorsal and, ventral structures is 

 one very widely shared, but is absent in- the lowest animals 

 which thus remind us of that earliest condition of man before 

 referred to, when his body is a minute spheroidal mass. 



A dorsal and ventral symmetry may be developed such as 

 man does not exhibit, and this is especially the case in the 

 region of the tail, where (as, e.g., irt fishes and amphibians) 

 the structures on the dorsal side of the centre of the back- 

 bone tend to be repeated on its ventral side. 



