Life of Plants and Animals 195 



jar of water, has a transparent appearance; the amoeba 

 has a constantly changing form, the paramecium a 

 permanent slipper-like form. This transparent gelati- 

 inous mass constituting the body of the cell is called 

 protoplasm, which has again been defined by Huxley 

 as the Physical Basis of Life. It is the substance 

 with which life and mind are associated, and without 

 which no life is supposed to exist. With substance 

 in this connection, it is necessary to understand not a 

 simple chemical mixture (some physiologists insist 

 that it is a chemical mixture) perhaps, but rather a 

 highly complex organized body consisting of various 

 substances blended and mixed, and held in a perma- 

 nent interrelation to one another while constantly 

 undergoing change. There is no known chemical 

 formula that can express the structure of protoplasm. 

 Neither is the chemical composition of living proto- 

 plasm known; for life ceases as soon as a chemical 

 analysis is made; and the change from living to dead 

 protoplasm is one of the most striking and also most 

 permanent changes in nature. For, while the change 

 from life to death is easily brought about, no case of 

 a transition from death to life is known to science. 

 In other words, these microscopic organisms in the 

 jar do not originate from dead substance, out of noth- 

 ing, nor spontaneously, but the vast multitude are 

 the offspring of one or more parent organisms like 

 themselves. Thus the bacteria originate from bacteria 

 and paramecia from paramecia. The substance of 

 both is protoplasm, which is so much alike in both 

 that we are unable to discover any profound differ- 

 ence even with the most powerful microscopes. That 

 the paramecia and bacteria, for instance, are so dif- 

 ferent not only in their size and form, but also in their 

 effects on other organisms, is supposed, by some, to 

 be due to a specific structure of the protoplasm, while 

 some radical physiologists insist that the difference 



