192 PROCEEDINGS OF THE SCIENTIFIC ASSOCIATION. 
Silicic anhyd ride . 
Calcium oxide 
Magnesium ,, 
Potassium „ 
Sodium ,, 
... 225,000 lbs. 
... 78,000 ,, 
... 28,500 „ 
... 174,300 „ 
... 69,300 ,, 
A consideration of the facts here set forth leads to the 
following conclusions respecting the disease in the canes 
at Orange Grove estate. Based as they are, however, on 
very limited analytical data, they are not necessarily in- 
tended to apply to other instances or to account for the 
disease generally. Respecting the canes, it has been shown 
that they exhibited great irregularity of growth, as mani- 
fested by the variation in length of the internodes, that they 
were stunted and of a dull and wrinkled exterior, all indi- 
cative of defective nutrition. The analysis of the ash proved 
them to be deficient in soda, phosphoric acid, and especially 
in silica. Analysis of the soil in which the plants were 
grown showed it to be poor and infertile. Its physical 
condition was bad, as it consisted almost wholly of clay ; 
no stones nor gravel, and only about 7*35 per cent, of sand 
being present. It is wofully deficient in phosphates, and in 
calcium, potassium, and sodium salts, while silicic anhydride, 
in a soluble form, is almost absent. On the other hand, the 
soil yields a quantity of black oxide of iron — a substance 
supposed to exert an injurious action on the roots of plants, 
and to be chiefly concerned in the production of a sour 
condition in land. Now it is highly probable that the 
defective assimilation of the plants may have been owing 
to the general poverty of the land, or else to the presence 
of the prejudicial black oxide of iron ; but it is equally 
probable that the absence of silicic anhydride in a soluble 
form is at the root of the mischief, for it is an established 
