272
THE ESSEX NATURALIST.
has persisted until recent years among the shepherds in Pem-
brokeshire, by whom the jelly is called "pwdre ser," or "the
rot of the stars." Some persons have actually described seeing
luminous bodies fall from the sky, and, on going to the spot where
they imagined they had reached the ground, finding there a mass
of jelly.
Many suggestions have been made as to the possible nature
and origin of this jelly-like material. It does not seem certain
that the jelly itself is ever luminous when found. Were one of
the suggestions correct, however—namely, that it consists of
food material thrown up by herons—luminosity would not be
altogether surprising, since there are frequently luminous
bacteria in decaying fish, and the breast-feathers of herons
are said to be often phosphorescent in consequence of their
habit of disgorging food. Some writers have attributed the
jelly to the remains of masses of worms disgorged by gulls, but
it is not clear that there is any direct evidence in favour of this
explanation.
In the correspondence which followed Professor Hughes'
article, various other theories were put forward, the prevailing
view apparently being that the jelly was probably the plasmodium
of a Myxomycete, a mass of algae, such as Nostoc, or the zoogloea
of some bacterial organism. None of the correspondents, how-
ever, seems to have been able to adduce definite evidence, or to
have actually compared the "pwdre ser" with the organism
mentioned. The most illuminating information came from
Dr. G. H. Pethybridge, who referred to a German paper by M.
Melsheimer, published in 1908, in which the "jelly" was
attributed to the remains of the oviducts of frogs. As long ago
as 1667 Merrett had stated his opinion that it consisted of the
viscera of frogs, left on the ground by crows. Melsheimer
elaborated the same idea, and actually performed experiments
by which he proved that the oviducts of frogs, dissected out and
left in a wet place, formed just such masses of jelly.
Professor Hughes himself was very near the mark when he
said that the jelly seen by him was "very like a mass of frog's
spawn without the eggs in it." This is, in fact, exactly what it is.
It has been the writer's good fortune recently to obtain specimens
which seem to prove quite definitely the nature of the jelly
(at least in some cases), and the manner in which it comes to