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NATURE 
49 

sensibility of the olfactory mucosa should be abolished 
by painting with a 20 per cent. cocaine solution; 
and then see if a bird such as a gull can balance and 
soar as well after painting as before. Plugging of 
the nostrils, or section of the nerves, can also be 
tried. The effect to look for is on the capacity for 
soaring and gliding flight, not of flapping flight. 
W. YP M'KEcHNIE, 
17 Chepstow Place, London, W.z2, 
December 15. 

Nature Study and Phenology. 
PHENOLOGY is the name given to that branch of 
meteorological science which has as its object the 
studied effect of weather conditions upon the seasonal 
development of animal and plant life. 
From the late seventies of last century, and since 
189r on a uniform tematic plan, the Royal 
Meteorological Society issued an annual report 
on phenology. This pat, by collating and co- 
ordinating the work of a number of observers— 
mostly amateurs—in the British Isles, is able to 
present in summary form, supplemented by tables 
and maps, information of a most valuable botanical, 
ornithological, and agricultural nature. 
Nevertheless, to accomplish such results, all that 
its observers are required to do is to note carefully ° 
the first appearance of certain birds and insects, 
twelve in number, and the first blooming of fourteen 
common plants: Other migrants and notes are 
asked for, but these are of secondary importance. 
Here is a work which should surely appeal to the 
Nature-lover. By simply recording a an observa- 
tions on a prescribed form, and forwarding the same 
promptly about November 15 (the close of the 
phenological year) to the Royal Meteorological Society, 
49 Cromwell Road, S.W.7, the work of the amateur is 
lifted from a purely local value to become a real link 
in the progress of scientific research. 
Stations are still urgently needed in many parts 
of our islands, and a copy of our observing form 
will be forwarded upon application to the office of 
the Society, or to one of us. 
J. E. CLark, 
41 Downscourt Road, Purley, Surrey. 
I. D. Marcary, 
o Chartham Park, East Grinstead, Sussex. 

Water Snails and Liver Flukes. 
Iy connexion with the letter on the above subject 
~in Nature of November 25, p. 701, I should like to 
ask Dr. Monica Taylor if she has actual proof of 
os eter into contact with Limnea peregra ? 
The habitat of this species is so much more ‘‘ watery ”’ 
than that normally chosen by L. truncatula that it 
seems very doubtful if sheep could eat it with their 
food. Again, L. truncatula is such a widely dis- 
tributed species that it seems difficult to believe 
that it is either rare in or absent from any district in 
which damp sedgy pastures are to be met with. 
Planks left undisturbed for a few weeks, or cut 
tushes shaken over a newspa after having lain 
on the ground for a time, might reveal the presence 
of L. truncatula in many places from which it was 
apparently absent. And what of L. palustris, the 
habits of which are often nearer to those of L. 
truncatula than L. peregra ? 
A. W. STELFox. 
National Museum, Dublin, 
December 12. 
NO. 2776, VOL. 111] 
REFERENCE to “ The Life-History of the Liver 
Fluke,’’ by A. P, Thomas (Q.J.M.S., 23, 1883), or indeed 
to almost any text-book in zoology, will show Mr. 
Stelfox that in order to become infected it is not 
necessary for sheep to eat the intermediate snail host 
of Fasciola hepatica. It suffices that the encysted 
cercarie be swallowed. The latter may be found at 
considerable distances from their snail host, for the 
tailed cercarie# which give rise to the encysted forms 
exist as such for about a week after they have escaped 
from the host and are extremely active. On account 
of their microscopic character (they are just visible 
to the naked eye as snowy specks) the merest trace 
of water suffices for their needs. The more“ watery "’ 
habitat of L. peregra, which is extremely common in 
all sorts of ditches, puddles, and streams, constitutes 
no impediment, therefore, to this snail acting as a 
disseminator of the liver-rot parasite granted that it 
can become properly infected. That it is capable of 
being infected and of setting free perfectly developed 
cercarie I have abundant evidence. 
In answer to my request for literature references 
to any host other than L. truncatula of the liver-rot 
parasite, Dr. Paul Pelseneer has kindly given me 
several, one of which (Lutz, Centralbl. f. Bakteriol. und 
Parasitenk., xi. pp. 781-796, 1892), since it refers to 
L. peregra as an intermediate host of Fasciola 
hepatica, may be of use to Mr. Stelfox. With regard 
to the first of the methods of discovering L. truncatula 
suggested by Mr. Stelfox, I have had negative results 
in some districts although the sheep in these same 
districts are infected. 
Monica TAYLor. 
Notre Dame, Dowanhill, Glasgow, 
December 16. 
Effect of Moonlight on the Germination of Seeds. 
DurinG the summer of 1921 [ investigated the 
effect of moonlight on the germination of seeds, and 
the results seemed to indicate a greatly increased 
velocity of germination. In order to determine 
whether this might be due to the effect of the moon- 
light on the diastase, a small quantity of mustard 
seed was crushed, and weighed quantities, after 
mixing with known amounts of water, were exposed 
to moonlight in Petrie dishes, controls set alongside 
being covered. Estimation with Fehling’s solution 
of the sugar produced showed that there was an 
increased yield of about 15 per cent. caused by the 
moonlight. 
A possible explanation of these results is to be 
found in the fact that at certain periods moonlight 
is plane-polarised, and in order to test this suggestion 
the experiments with crushed mustard seed were 
repeated with daylight after polarisation, either by 
reflection or by a Nicol prism. Control experiments 
were also carried out both in darkness and in ordinary 
daylight. The temperature was the same for all 
three experiments in each case and lay between 
10° and 18°. A remarkable increase in the amount 
of hydrolysis was always noted when polarised light 
was used. Similar results were obtained with fresh 
oats, wheat, and cornflour, to which diastase had 
been added. 
The investigation of this phenomenon is now 
being continued at Liverpool in conjunction with 
Prof. E. C. C. Baly and Prof. J. McLean Thompson, 
and the results already obtained are worthy of 
record since they give strong support. Diastase is 
added to a suspension of freshly prepared starch 
and the mixture well shaken. A drop of the mixture 
is placed on three slides under microscopes, one 
B2 
