30 HOW CROPS GROW. 
Organic matters are in general characterized by com- 
plexity of constitution, and are exceedingly numerous and 
various; while inorganic bodies are of simpler composi- 
‘tion, and comparatively few in number. 
Vouatite anp Fixep Matrer.—All plants and animals, 
taken as a whole, and all of their organs, consist of a vola- 
tile and a fixed part, which may be separated by burning; 
the former—usually by far the larger share—passing into, 
and mingling with the air as invisible gases; the latter— 
forming, in general, but from one to five per cent of the 
whole—remaining as ashes. 
EXPERIMENT 1.—A splinter of wood heated in the flame of a lamp 
takes fire, burns, and yields volatile matter, which consumes with flame, 
and ashes, which are the only visible residue of the combustion. 
Many organic bodies, products of life, but not essential 
vital organs, as sugar, citric acid, etc., are ccapletely 
volatile when in a state of purity, and leave no ash. 
Current Usr or THE TrRms Orcanic AND InorGAN- 
1c.—It is usual among agricultural writers to confine the 
term organic to the volatile or destructible portion of vege- 
table and animal bodies, and to designate their ash-ingre- 
‘dients as inorganic matter. This use of the words is ex- 
tremely inaccurate. What is found in the ashes of a tree 
or of a seed, in so far as it was an essential part of the or- 
ganism, was as truly organic as the volatile portion, and by 
submitting organic bodies to fire, they may be entirely 
converted into inorganic matter, the volatile as well as the 
fixed parts. 
UitimaTe ELEMENTs THaT ConsrTiTuTE THE PLanT.— 
Chemistry has demonstated that the volatile and destruct- 
ible part of organic bodies is made up chiefly of four sub- 
stances, viz.: carbon, oxygen, hydrogen, and nitrogen, 
and contains two other elements in lesser quantity, viz: 
sulphur and phosphorus, In the ash we may find phos- 
phorus, sulphur, silicon, chlorine, potassium, sodium, cal- 
