266 FIRESIDE SCIENCE. 



method of appropriating it, differs from that of 

 animals, there are analogies not only apparent but 

 real between them. In animals we have the res- 

 piratory functions, and so we have in*plants, for 

 plants breathe as truly as we do ourselves ; we re- 

 quire our food to be composed of certain ele'ments 

 arranged in certain combinations, so do plants ; 

 we find it essential that our food should be in par- 

 ticular forms or mechanical conditions, so do 

 plants ; we must be regularly supplied with food, 

 and this is the case with plants. These are some 

 of the similarities existing between plants and ani- 

 mals, and serve to show how intimate is the relation 

 which subsists between plants and the higher forms 

 of organized structures. 



Although we have learned with certainty re- 

 garding the elements essential to plants, and also 

 the forms of combination required, we have yet to 

 learn the exact mode in which they acquire their 

 food, and how they are able to build up such bodies 

 as cellulose, starch, albumen, oil, etc., from these 

 elements. No processes which chemists venture 

 upon in the laboratory are found so difficult as the 

 synthetical production of organic compounds. In- 

 deed, organic chemistry has thus far proved totally 

 incompetent to instruct how to form any one of 

 these bodies from the elements, and for their elab- 

 oration we must look solely to the vital chemistry 

 of animals and plants. 



