702 
THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS. 
[March 2,1872. 
of barley, oats, maize, and beans. I have never 
detected mineral matter, nor indeed anything in¬ 
jurious beyond the occasional spores of fungi ( Puc- 
cinia, Credo and Ustilago). The examination of 
wheat-flour will follow the same general directions 
as that of arrowroot, with the addition of testing for 
mineral matter, if any be suspected. This may very 
conveniently be done on the stage of the microscope, 
when the presence of the smallest quantity of lime, 
in the form of “bone-dust” or “ sulphate,” may be 
detected. The process is simply that of applying 
the usual reagents to a small quantity of the flour 
whilst it is under view, use of the mixed glycerine 
and water being omitted, and the reagents applied be¬ 
neath the covering glass. 
I have not found the microscopic examination of 
bread to be of any great use. The usual chemical 
process had better be followed if the presence of 
alum or sulphate of copper be suspected. Potatoes 
may sometimes be found by aid ‘of the microscope, 
but not often; rice I think never. Beans and barley 
may be glimpsed, but “not sworn to.” 
We have now concluded the easy part of our 
lesson. For the prosecution of our study some 
knowledge of minute structural botany is necessary, 
and may be obtained from the careful study of such 
books as the English translation of Schleiden’s 
‘ First Principles ’ (Hardwicke), Henfrey’s ‘ Botany ’ 
(Masters’s edition, Van Voorst), Bentley’s ‘Botany,’ 
and last, but least only in size and price, the excel¬ 
lent little manual by Mr. M. C. Cooke (Hardwicke). 
Young men unembarrassed by the cares of business 
will doubtless follow the thorough course of training 
necessary to enable them to become good vegetable 
histologists as a preparation for the duties of the 
analyst. But many who have the w illin gness to 
undergo this course of study are so occupied with 
the cares of their businesses and families as to be 
obliged to content themselves with the smallest 
modicum of structural knowledge, and may be grate¬ 
ful for a brief outline of the histological charac¬ 
teristics of the various parts of plants made use of 
in pharmacy or food, so far as such characteristics 
are recognizable in the official preparation or com¬ 
mercial article. These parts are, the underground 
and aboveground stems, foliar organs (flowers and 
leaves) and reproductive organs (stamens, fruits, etc.). 
We will briefly consider them in the order given. 
(To be continued.) 
VESICATING- INSECTS. 
BY M. C. COOKE, M.A. 
{Continued from page 584.) 
Coubbon’s Blister-fly, Lytta Courboni, Guerin. 
—Guerin; Bevue et Mag. de Zool. 1855, p. 590. 
Lytta vidua, Courbon, Comptes Iiendus, 1855, t. xli. 
p. 1005 (not Klug). 
This insect is from 22 to 27 millimetres in 
length. It is entirely black, presenting only at 
the posterior extremity of the elytra a very small, 
slightly marked whitish edge or embroidery. It is 
very common, though much less so than the dotted 
species. It lives on two leguminous plants, the 
Adesmia pendula and the Adesmia punctata, DC. 
but especially on the former plant, which covers the 
Cerro ot Montevideo, and on the flowers of which it 
feeds. “ I have only met with it,” writes M. Courbon, 
“ in the months of November, December, and January, 
the periods at which the above-mentioned plants are 
in flower. This insect may be collected like the 
dotted blister-fly. Its blistering properties are, at 
least, as energetic as those of the officinal cantliarides. 
Although less common than the beet cantliarides, it 
might yet be employed with considerable advantage, 
on account of its large dimensions. It would be in¬ 
teresting to decide whether it shapes the valuable 
property of the dotted cantliarides. I much regret 
not having been able to make experiments on this 
point.” 
Courbon referred this insect in his communication 
to the Lytta vidua of Klug, and specimens were 
deposited by him in the Museum of Natural History 
in Paris. Guerin has examined these specimens, 
and determined that they do not belong to the 
species to which Courbon referred them,* so that he 
has proposed for them a new name, which we have 
adopted. Klug’s blister-fly is also included in our 
list, on the authority of Moquin-Tandon (Med. Zool.). 
The concluding observations of M. Courbon, in 
his paper, which has furnished the information 
already quoted, is too pertinent to be omitted. “ In 
these three cantliarides,” he says, “the blistering 
principle resides exclusively in the soft or inner 
parts; the outer, or hard horny parts, which form 
the skeleton of these insects, do not possess any 
epispastic property. I at first thought that the soft 
parts of the abdomen and thorax had the privilege 
of being the exclusive seat of the active principle, 
relying on what had been written by M. Farines, of 
Perpignan, in 1835, namely, that this was the case 
with the officinal cantliarides; but I have ascertained, 
by repeated experiments, that the soft parts of all 
regions possessed the same property. Thus the in¬ 
terior parts of the head and thighs, which I used 
separate^, possess a power as great as do the inner 
parts of the abdomen and thorax, while the frame¬ 
work of these regions, to which we must add the 
antenme and those portions of the feet which are 
composed of hard material, are completely inert. I 
made these experiments separately for the three 
Montevidean species, and also with the same results 
on the officinal cantliarides.” 
Klug’s Blister-Fly, Lytta vidua, Klug; black; 
thorax, margin of 
etytra and base of the v V*'" 
tibne whitish.—Klug 
Nova Acta Nat. Cur. 
Causima vidua, Dej. T 
Length 8-10 lines. // JP 
Head large, subcor- M Jam lift 
date, punctate late- 
rally, and the palpi if jmC v- 
cinereo-villose. Ej^es ^ 
emarginate, testa- 1 m 
ceous. Antenme xjF 
short, cinereo-villose. £ ^ 
Thorax short, un- ^ 
equal, plane, im-» Lig. 13 .—Lytta vidua. 
pressed in the middle, punctate, subpilose, black, 
posterior margin whitish. Scutellum indistinct. 
Elytra punctato-rugose, somewhat triline ate; outer 
margin and apex whitish-ciliate. Breast punctate, 
fuseo-pilose, margin whitish. Abdomen punctate; 
segments albido-ciliate. Feet black, tibia whitish- 
pilose. 
* Guerin, Revue Zool. 1855, p. 590. 
