DIFFERENCES IN ANIMAL AND 

 PLANT LIFE. 



By F. CARREL. 



In biology no essential difference is considered to exist between 

 animal and vegetal life. Resemblances of reproduction, cell- 

 construction and development, nutrition, digestion, and 

 metabolism are observable in the two states. Some organisms 

 partake of the nature of both kingdoms. Some spores and 

 leaves of plants are motile, and a few animals possess 

 characteristics which are common in plant life. 



For these reasons the life-principle is held to be identical 

 throughout living nature. 



But when the word principle is used in this connection, it 

 is necessary to be clear as to its meaning. What is termed the 

 principle of life is evidently that series of circumstances 

 whereby organised matter is enabled to stand for a space of 

 time in accretional and assimilatory relationship with the 

 environment. The circumstances are common to both plants 

 and animals, but there are differences in the way in which the 

 relationships occur, and these differences are great enough to 

 divide the manifestations of the principle into two parts which 

 may be called the major and the minor according as they are 

 produced in animal or vegetal form. 



In the vegetal form, as is well known, the non-parasitic 

 organism derives its nutriment from the soil l and air, and not 

 directly from the flora or the fauna (except partly in the case of 

 insectivorous plants) which surround it. ? It is thus dependent 

 upon the gases which it obtains from the air, and the salts which 

 it derives from the soil as well as upon water. It possesses no 

 real nervous system, no blood to act as a distributor of nutri- 

 ment, but is indebted to the influence of chlorophyll and sunlight 



1 Although the bacteria in the soil which convert nitrogen compounds into 

 a mmonia are the means of supplying ammonia to plants, they are, of course, not 

 themselves plant-food. Neither are the symbiotic fungi of the roots of forest trees 

 directly alimentary. 



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