20 STRUCTURAL COMPOSITION OF HUMAN BODY. 



sented itself most strongly to the minds of its observers. 

 In the bodies of the lowest animals, as the Rhizopoda or 

 Gregarinida, of which it forms the greater portion, it has 

 been called " sarcode," from its chemical resemblance to the 

 flesh of the higher animals. When discovered in vegetable 

 cells, and supposed to be the prime agent in their con- 

 struction, it was termed " protoplasm." As the presumed 

 formative matter in animal tissues it was called " blastema;" 

 and, with the belief that wherever found, it alone of all 

 matters has to do with generation and nutrition, Dr. Beale 

 has surnamed it " germinal matter." 



So far as can be discovered, there is no difference in 

 chemical composition between the protoplasm of one part or 

 organism and that of another. The movements which can, 

 be seen in certain vegetable cells apparently belong to a sub- 

 stance which is identical in composition with that which 

 constitutes the greater portion of the bodies of the lowest 

 animals, and which is present in greater or less quantity 

 in all the living parts of the highest. So much appears 

 to be a fact; that in all living parts there exists an albu- 

 minous substance, in which in favourable cases for observa- 

 tion in vegetable and the lower animal organisms, there 

 can be noticed certain phenomena which are not to be 

 accounted for by physical impressions from without, but 

 are the result of inherent properties we call vital. For 

 example, if a hair of the Tradescantia Virginica, or of 

 many other plants, be examined under the microscope, 

 there is seen in each individual cell a movement of the pro- 

 toplasmic contents in a certain definite direction around the 

 interior of the cell. Each cell is a closed sac or bag, and its 

 contents are therefore quite cut off from the direct influence 

 of any motive power from without. The motion of the 

 particles, moreover, in a circuit around the interior of the 

 cell, precludes the notion of its being due to any other 

 than those molecular changes which we call vital. Again f 

 in the lowest animals, whose bodies resemble more than 



