2 THE HUMAN BODY 



conception of complexity which may be thus arrived at from ex- 

 ternal observation of the living, is greatly extended by dissection 

 of the dead Body, which makes manifest that it consists of a great 

 number of diverse parts or organs, which in turn are built up of a 

 limited number of materials ; the same material often entering into 

 the composition of many different organs. These primary^ build- 

 ing materials are known as the tissues, and that branch of anatomy 

 which deals with the characters of the tissues and their arrange- 

 ment in various organs is known as Histology; or, since it is mainly 

 carried on with the aid of the microscope, as Microscopic Anatomy. 

 If, with the poet, we compare the Body to a house, we may go on to 

 liken the tissues to the bricks, stone, mortar, wood, iron, glass and 

 so on, used in building; and then walls and floors, stairs and win- 

 dows, formed by the combination of these, would answer to ana- 

 tomical organs. 



Zoological Position of Man. External examination of the Hu- 

 man Body shows also that it presents certain resemblances to the 

 bodies of many other animals: head and neck, trunk and limbs, 

 and various minor parts entering into them, are not at all peculiar 

 to it. Closer study and the investigation of internal structure 

 demonstrates further that these resemblances are in many cases not 

 superficial only, but that our Bodies may be regarded as built upon 

 a plan common to them and the bodies of many other creatures: 

 and it soon becomes further apparent that this resemblance is 

 greater between the Human Body and the bodies of ordinary four- 

 footed beasts, than between it and the bodies of birds, reptiles or 

 fishes. Hence, from a zoological point of view, man's Body marks 

 him out as belonging to the group of Mammalia (see Zoology), 

 which includes all animals in which the female suckles the young; 

 and among mammals the anatomical resemblances are closer and 

 the differences less between man and certain apes than between 

 man and the other mammals; so that zoologists still, with Lin- 

 naeus, include man with the monkeys and apes in one subdivision 

 of the Mammalia, known as the Primates. That civilized man is 

 mentally far superior to any other animal is no valid objection to 

 such a classification, for zoological groups are defined by ana- 

 tomical and not by physiological characters; and mental traits, 

 since we know that their manifestation depends upon" the struc- 

 tural integrity of certain organs, are especially phenomena of 



