SCIENTIFIC SUMMARY. 
85 
above alluded to, and, having thus gained a partial entrance, it would defeat 
its intention, did not the length of the flower’s tube when contrasted with 
that of the bee’s trunk, necessitate the admission of the entire head also. 
In this operation the lips of the flower are pressed apart, the margins of 
the upper lip are separated to receive the head, and the pollen- grains, 
already ripe, by the considerable motion to which they are subjected, 
become dislodged from their cells, and fall down in a dense shower upon 
the bee’s back and head. Having obtained the coveted sweet, it flies to 
another flower upon a different stalk, as he observed in a score of cases 
during two days, but, before renewing the preceding operations, stations 
itself awhile upon the lower lip, its head coming in contact with the stigma 
of the pistil. Then, by means of the hairs that line the inner side of the 
tarsus of each anterior leg, and the constant rubbing together of the parts 
comprising its trophi or instrumenta cibaria, the attached pollen-grains are 
sent flying in every direction, sure to adhere to the stigma. 
What is the Nature of the Hollyhock Disease? — It seems that during the 
months of June and July this disease was reported from different localities 
in England as having caused considerable damage to Hollyhocks. It is 
produced, says a note in il Grevillea,” by Puccinia malvacearum (Mont.), a 
fungus not previously observed in this country, which was originally 
described by Montagne as occurring on the under surface of the leaves of 
Altlicea officinalis. The Editor has also received specimens on Malva sylvestris , 
from J. Hussey, Esq., of Salisbury $ Dr. Paxton, of Chichester ; and Mr. 
E. Parfitt, of Exeter. 
CHEMISTRY. 
Estimation of Tannin in Tea-leaves. — This, which might at one time have 
been considered a purely physiological subject, has now in these days of 
“ Chemical” Officers of Health, become a very serious and important 
problem. In the 11 Chemical News ” for October 24, 187-3, appears a 
paper on this subject. Its author, Mr. A. H. Allen, F.C.S., after giving a 
number of matters of interest, describes the details of the method he em- 
ployed in the estimation of tannin, stating that he had found by the pro- 
cess in genuine black tea of rather more than average quality 12-5 per cent, 
of tannin, which presented a close agreement with those in the old analyses 
of Mulder, which he regarded as the most accurate and complete analyses 
of tea extant. The estimation of tannin was of the first importance ; for if 
it reached the normal amount, all question of adulteration by exhausted 
leaves was at an end, and foreign leaves were very unlikely to be present. 
The only fallacy in such a conclusion would be caused by an admixture of 
catechu, or sloe-leaves. The next point of importance was the percentage 
of u woody fibre,” as it was called by some analysts ; and here, again, he 
was disposed to think that Mulder’s analysis was the only accurate one. 
The percentage of gum, insoluble matter, and tannin in any sample of tea, 
considered carefully, would enable the analyst to form a very accurate 
opinion as to the presence or absence of exhausted leaves, &c. Analysed 
