PRINCIPLES OF GENERAL 

 PHYSIOLOGY 





ELEMENTARY PROPERTIES 



AT the very outset of our studies we are faced by one of the most difficult 

 problems with which the biologist has to deal, namely, the structure, chemical 







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FIG. 1. AMOEBA PROTEUS(?). Creeping in direction of arrow. Projecting 

 in advance clear pseudopodia. The contractile vacuole is seen in the 

 posterior end of the organism. Each division of the scale corresponds 

 to 2-5 /*. (Leidy, 1879, PI. iv. fig. 22.) 



and physical, and the elementary properties of protoplasm. This substance is 

 met with in all living cells, but in various degrees of differentiation into more 

 specialised structures. In its simplest form, as seen in the pseudopodia of the 



