2 BOTANY. 



rily complex compounds. The following elements appear to 

 be essential to all living bodies : carbon, hydrogen, oxygen, 

 nitrogen, sulphur, potassium. Besides these there are several 

 others usually present, but not apparently essential to all 

 organisms. These include phosphorus, iron, calcium, sodium, 

 magnesium, chlorine, silicon. 



As we examine more closely the structure and functions of 

 organic bodies, an extraordinary uniformity is apparent in all 

 of them. This is disguised in the more specialized forms, but 

 in the simpler ones is very apparent. Owing to this any 

 attempt to separate absolutely the animal and vegetable king- 

 doms proves futile. 



The science that treats of living things, irrespective of the 

 distinction between plant and animal, is called " Biology," but 

 for many purposes it is desirable to recognize the distinctions, 

 making two departments of Biology, Botany, treating of 

 plants ; and Zoology, of animals. It is with the first of these 

 only that we shall concern ourselves here. 



When one takes up a plant his attention is naturally first 

 drawn to its general appearance and structure, whether it is a 

 complicated one like one of the flowering plants, or some hum- 

 bler member of the vegetable kingdom, a moss, seaweed, 

 toadstool, or even some still simpler plant like a mould, or 

 the apparently structureless green scum that floats on a stag- 

 nant pond. In any case the impulse is to investigate the form 

 and structure as far as the means at one's disposal will permit. 

 Such a study of structure constitutes "Morphology," which 

 includes two departments, gross anatomy, or a general study 

 of the parts ; and minute anatomy, or " Histology," in which 

 a microscopic examination is made of the structure of the 

 different parts. A special department of Morphology called 

 "Embryology" is often recognized. This embraces a study 

 of the development of the organism from its earliest stage, 

 and also the development of its different members. 



From a study of the structure of organisms we get a clue 



