1 18 
Notes. 
be removed by gently warming the slide over a flame. Then the 
superfluous fluid is drawn off by blotting paper, and the gelatine 
is allowed to dry and harden. During this process it should be 
exposed to a bright light. The action of the light on the bichromated 
gelatine renders it quite insoluble even in warm water, and so re- 
moves all danger of the sections becoming detached from the slide. 
The bichromate of potash in the gelatine has this additional ad- 
vantage, that after exposure to light it prevents the latter from taking 
up the dyes used as stains. So far as I have at present tested it, 
this preparation of gelatine is unaffected by saffranin, fuchsin, acid 
fuchsin, haematoxylin, iodine green, gentian violet, and aniline blue. 
With aniline blue, however, a precipitate is sometimes formed along 
the line which formed the edge of the paraffin ribbon and in cracks 
in the ribbon ; but in no case is the substance of the gelatine itself 
stained, and so it offers a marked advantage over albumen and 
agar-agar. 
HENRY H. DIXON. 
Trinity College, Dublin. 
LATHRAEA SQUAMARIA. — I find that in my paper on this 
subject, which appeared in Annals of Botany, Vol. xi, 1897, P- 3^5, 
I omitted to include in my references to the literature the observations 
of C. Darwin and F. Darwin, of which an account is given in ‘ The 
Power of Movement in Plants ’ (footnote, p. 85). The authors show 
that Lathraea can excrete large quantities of water underground, and 
state that the water is secreted by glands lining the cavities of 
the scales. 
PERCY GROOM. 
