2 ELEMENTARY ANATOMY. [LESS. 



the general science of organic forms, i.e. the science of 

 Morphology. 1 



2. The body of man has a more or less rounded outline, 

 and its various surfaces are curved. Moreover, as everyone 

 knows, it is made up of different parts and organs hard and 

 solid structures (bones) being enclosed by soft and pulpy 

 flesh. Indeed nearly all parts of man's body contain much 

 water : thus even 70 per cent, of the human brain is com- 

 posed of that fluid. 



As to chemical composition, most ingredients of the human 

 body (unlike the fat) contain nitrogen ; while a peculiar 

 organic substance termed protein" 2 (formed of the gases 

 oxygen, hydrogen, nitrogen, and of the solid element carbon) 

 constitutes its basis and foundation. 



3. Man's body is evidently divisible into head, trunk, and 

 limbs. 



Certain symmetrical relations and contrasts between dif- 

 ferent parts of the human frame are obvious. 



Thus there is a contrast between its anterior and its hinder 

 aspect, and this contrast extends along each limb to the ends 

 of the fingers and toes. The hinder aspect in all cases is 

 termed " dorsal," the anterior one " ventral/' and, indeed, we 

 familiarly speak of the back of the hand. 



Again, there is a resemblance (and at the same time a con- 

 trast) between the right a-nd left sides, which correspond with 

 tolerable exactitude one to the other. This harmony, termed 

 bilateral symmetry, though obvious externally, does not in 

 man extend to the internal organs (or viscera), which are 

 more or less unsymmetrically disposed. 



Thirdly, there is a resemblance and correspondence between 

 parts placed successively, as, for example, between the arm 

 and the leg, or between the hand and the foot ; although this 

 relation is less obvious than it might be, owing to the differ- 

 ent directions in which the knee and elbow are bent. Such 

 a symmetry is termed serial, and is thus externally visible ; 

 but it is more manifest on a deeper examination, where we 

 find successive parts like the ribs or the pieces of the back- 

 bone, which obviously resemble each other more or less, and 

 so are called by a common name, while as they are placed 

 in " series " they are excellent examples of serial symmetry. 



4. As is familiar to all, man's body consists of a solid frame- 



1 Morphology, from the Greek words iiop<pti, form, and Xo>C> discourse. 



2 Protein, from TrprTcroc, first; Trpcorei'ic/i/, to be the first; irptareiov, the first 

 place ; because it holds the first place in relation to the albuminous principles. 



