SECTION I. 

 THE STRUCTURE OF ORGANIZED BODIES. 



CHEMICAL ANALYSIS has shown that all organized bodies are capable 

 of resolution into simple chemical elements which in themselves do not 

 differ from the elements out of which all matter is composed : in other 

 words, that the simple elements of which organized bodies are built up 

 are universally distributed throughout nature, and that no one element 

 is peculiar to organized matter. The characteristic of organized bodies 

 is, therefore, not to be found in any peculiarity of the matter of which 

 they are composed, but in the manner in which the atoms composing 

 that matter are grouped. In an inorganic body we are accustomed to 

 attribute its chemical properties to the nature, number, and mode of 

 association of its constituent elements, while its physical properties are 

 attributable to the mode of arrangement of its molecules. 



Anatysis of organized bodies shows that in them we have certain 

 elements constantly present in certain definite proportions: it is there- 

 fore warrantable to assume that the chemical properties of organized 

 bodies are, as in the case of inorganic matter, due to the number, nature, 

 and mode of association of their elements. Further, we find in all 

 organized living bodies a certain identity of physical properties : it is 

 therefore warrantable to assume that the physical processes seen in 

 organized bodies are dependent on the mode of arrangement of their 

 constituent molecules. The elements constantly associated in living 

 matter are carbon, nitrogen, oxygen, hydrogen, and sulphur, forming a 

 complex combination, to which the term protoplasm has been applied. 

 This matter, protoplasm, whether found in the tissues of the highest 

 animals or plants, or in the lowest unicellular members of either kingdom, 

 has always the same composition and is always possessed of nearly the 

 same attributes ; with the restriction that we have already referred to as 

 to the difference in functions possessed by animals and plants, differences 

 which will probably in the future be cleared up, and found not to be in 

 contradiction to the statement that protoplasm is the universal basis of 

 organization. 



All organized bodies are built up of associations of masses of proto- 

 plasm, which from their appearance are termed cells, or, from the func- 

 tions which they fulfill, elementary organisms: and as the physical 

 properties of inorganic matter are dependent on the arrangement of 



