CHEMICAL ANALYSIS, 167 
They were all made in duplicate, except when indicated 
otherwise, and the results of each duplicate analysis are 
entered under columns A and B of each subhead, Fol- 
lowing this is a column headed ‘‘ Mean,” showing the 
mean content of each particular substance as indicated 
by the single or duplicate analyses. For the purpose of 
more direct comparison tbe component parts of the sey- 
eral samples have been calculated to material free of 
carbonic acid and unburned carbon, and these results 
are given under the column marked CO,-+-C free, 
Since, in the case of the root, it was almost impossible 
to exclude the sand, which was present as an impurity, 
the data have also been calculated to substance free of 
silica and carbonic acid and unburned carbon. ‘These 
data are contained in the column marked CO,+-C-+LSi0, 
free. This explanation will enable you to understand 
sufficiently well the tabulation of the results. 
As you will notice by the table, comparisons are made 
directly between the same parts, as nearly as possible. 
For instance, the quince fruit affected by rot is com- 
pared directly with the quince fruit of a healthy nature, 
although partially decayed from natural causes. In the 
same way the ash of the roots of the healthy tree is com- 
pared with the ash of the roots of the tree killed by 
borers, and in a like manner the ash of the twigs of the 
healthy tree is compared directly with the ash of the 
twigs of the tree killed by the fungus. The ash of the 
tree killed by borers is compared also directly with the 
ash of the tree killed by blight. The above, I hope, will 
be a sufficient description of the tables to enable you to 
understand them thoroughly. 
In regard to the lessons which these per cents teach, 
a few conclusions may be drawn from a study of the 
analytical results. The diseased quince fruit is decid- 
edly richer in silica than that of the healthy fruit, while, 
on the other hand, the healthy fruit contains a large 
