140 
HiEMATOXYLUM CAMPECHIAN UM. 
deep yellow colour ; the stamens are downy, shorter than the petals, 
and crowned with smaller oval anthers ; the style is about the length 
of the filament ; the germen is obovate, and becomes a large double- 
valved pod, containing four or five kidney-shaped seeds. 
We are told by Miller,* that the seeds which are brought from 
America, *' if fresh, readily grow when sown upon a good hot-bed ; 
and if the plants are kept in a moderate hot-bed, they will grow to 
be a foot high the same year ; and while the plants are young they 
are generally well furnished with leaves, but afterwards they make 
but little progress, and are frequently but thinly clothed with leaves. 
The plantis are very tender, so should be constantly kept in the back- 
stove, where, if they are duly watered, and the stove kept in a good 
degree of heat, the plants may be preserved very well." 
The wood of this tree (the officinal part) is imported into this 
country chiefly as a dye stuff. It comes to market in logs or junks, 
about three feet in length, and varying in diameter ; these are subse- 
quently cut into slips. The largest logs are preferred, being of a 
deeper colour. 
Sensible and Chemical Qualities, &c. Logwood is in- 
odorous, but has a sweet styptic taste ; it is compact, hard and 
heavy, and of a deep brownish red colour, which it gives both to 
water and alcohol ; the watery infusion instantly strikes black with 
sulphate of iron. Sulphuric acid dilutes the colour of the watery 
infusion, and on saturating the acid with salt of tartar, it becomes 
dark violet, but on dilution soon changes to an aurora colour ; 
nearly the same change takes place if the salt of tartar be added to 
the infusion itself. The tincture is blood red, which is scarcely 
altered by sulphuric acid, and on saturating it with salt of tartar it 
turns rather purplish, and yields a thick sediment, which on adding 
water is dissolved, and the tincture becomes violet.f According to 
Chevreul, logwood contains tannin, two kinds of colouring matter, 
(one soluble in alcohol only, the other soluble both in alcohol and 
boiling water,) volatile oil, acetate of potass and of lime, and a 
peculiar substance which he has named hematin.J Hematin is ob- 
tained by infusing logwood in warm water, filtering the liquid, evapo- 
rating to dryness, and digesting the extract in alcohol, sp. gr. 
0.837, filtering the tincture, and evaporating off part of the spirit. 
* "Vide Card. Diet. 
+ Gray's Elements. 
J Annales de Chimie, Ixvii. 254. 
