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BOTANICAL NEWS. 215
He asserts that my " observations* are not confirmed by other authorities."
This is not quite true, for I see them approved of on all sides, and I am confi-
dent Dr. Lindsay's authority will not suffice to invalidate them.
The colouring efi'eets produced by chloride of limef are generally very evi-
dent ; but the reagent must necessarily be of good quality, and has to be renewed
when enfeebled by exposiu*e. In some lichens, however, in several TJm-
bilicarice for instance, the erythriuic reaction is typically weak ; in which case
this weakness is itself characteristic.
The other newly proposed agent, hydrate of potash {hydras Tcalicus or kali
causticum) ,Yik.ev;ise frequently offers but faint reactions, especially in Cladoniei,
but it is not less indisijensable in the discrimination of their species. The re-
actions of lecanoric acid (yellow and red) are, generally speaking, very clear (in
Parmeliei, Lecanorei, etc.) ; those of chrysophanic acid are still more so.
The instrument I use for applying the reagents is a goosequill sharpened into
a point ; with this I touch but a very small extent either of the cortical layer
(or the apothecia) or of the medulla, observing at the same time the efiects of
the application through a magnifier. My researches have proved that these
means often afford the best, the surest, and the easiest way of recognizing a
great number of Lichens. To Dr. Lindsay, then, who is of an opposite opinion,
it only remains for me to apply what I have elsewhere written in an analogous
case : " Eos, qui erroribus sunt dediti, nuUa castigatio acrior attingere potest
quam si errores suos conservant et in falsis computationibus permanent."
I am, etc.
Faris, June, 1869. W. Nyiandee, M.D.
BOTANICAL NEWS.
The Trustees of the British Museum have established an additional assistant-
ship in the Botanical Department, and we congratulate them on the appointment
of so able and promising a botanist as Dr. Henry Ti-imen to the new
office. He entered on his duties early in May last.
Dr. Seemann returned to England on the 12th of last month, after an absence
of several months in Central America and the Isthmus of Panama.
The ' Gardeners' Chronicle ' is authorized to contradict the report that it
* They are entirely independent of those of the Rev. W. A. Leighton, who
has made a series of applications of my discovery to Cladoniei.
t This is the powder of Tennant and Knox (in Latin hypochloris calcicus,
oxymurias calcius, or calx oxymuriatica), in no way " hypochlorite of calcium^'
as written by Dr. Lindsay, who has made use of a pharmaceutical preparation
of doubtful value. Nor are tincture of iodine and its aqueous solution identical
as regards their reactions. Dr. Lindsay is consequently wrong in saying, " I
am not aware of any advantage tliis solution" (the aqueous one with the addition
of iodide of potassium) " possesses over our officmal tincture of iodine,
diluted with water to such extent that the liquid has only a pale sherry colour."