MOON BELIEFS AND MODERN BIOLOGY
MOON beliefs are legion. Almost all human activities have in turn been supposed to be influenced by the moon. This is not at all surprising. The moon's rhythm is one of the most evident rhythms in nature. Primitive man would naturally find a causal connexion with human rhythms.
Until the Revolution, French forestry law prescribed planting and cutting at definite phases of the moon, while to-day in England old gardeners follow the moon for sowing. Nevertheless no foundation of fact has been found for such beliefs. In one instance botanical research has recently show that the whole story is quite false. From the times of Aristotle and of -Pliny down- wards it has been stated that various fruits, particularly cucumbers, grow most rapidly at full moon. The error of this has now been demonstrated. - But turn now to a moon belief which is justified. The facts are these. At Suez the spiny shell-fish known as the sea-urchin is esteemed a delicacy, as also all around the Mediterranean. There is little meat in these shell- fish, except the ovaries, which are eaten raw with vinegar and lemon. Now, it has been shown at Suez lately that the size of- these ovaries varies with the phases of the moon. Round• about full moon the ovaries are big, near the time of new moon they are shrunken. So that the popular belief is justified. The exact sequence of events is this. During the few days before and after full .moon the sea-urchins spawn. The eggs are shed into the sea, so that the-'ovaries become shrunken.
Immediately afterwards preparations are begun inside each ovary, for the production of a new crop of eggs. At first these changes are on a microscopic scale, so that when the new moon, comes round the ovaries are still shrunken, and incidentally are not worth eating. But with the waxing moon the new crop of eggs swells in size, until, just before full moon, .the ovaries are again plump. They have once more become succulent morsels and will again spawn into the sea, unless eaten first.
Although the details of this most curious cycle are now known, its cause and the connexion with the moon's phases remain unknown. At. first the tides would be suspected. The tides are known to impose a rhythm on the reproduction of other marine animals and of sea-weeds. Yet there are two spring tides in each lunar month, but the Suez urchins have one, not two rhythmic cycles per moon. Further research is required before the link between the moon and the urchins can be discovered. It may be an influence of the light of the moon, or it may be a phenomenon due to variations in atmospheric electricity having a lunar period.
The lunar periodicity of the Suez urchin is sufficiently remarkable in itself. It becomes much more remarkable when considered in relation to popular beliefs. Such beliefs about the moon's influence on shell-fish are both widespread and ancient. Not only at Suez is it thought to-day that urchins are only worth eating at full moon. The same statement is made in all the ports of the Mediterranean, at Marseilles, at Nice, at Naples, in Greece, at Alexandria. More than this, the same thing is said of oysters and of mussels. And this belief is by no means new. It was held by the ancient Greeks and Romans, and believed so generally that not only the philosophers, but the poets and orators refer to it. Aris- totle (De Part. Anim.) most precisely, tells us that the ovaries of sea-urchins acquire a greater size than usual at the time of full moon. Oppian, in his poem on fishing, the " Halieutica," writes as follows : " The shell-fish which creep in the sea are said, all of them, when the moon waxes to fill up with flesh proportionately to her disc, occupying then a bigger space. On the other hand, when she wanes they shrivel and their members grow thinner." Cicero (De Div.), too, says that this is true of all shell-fish, and Horace (Sat. IV.) mentions that " nascent moons fill the succulent shell-fish." Pliny (Hist. Nat.) makes several references to the subject. He says that "learned men have ascertained that the bodies of whelks, crabs and echini increase and again decrease under the moon's' influence."
In 1627 Francis Bacon referred to the same subject. Very characteristically he suggested an experimental enquiry. He said that " the opinion received is that brains in rabbits, woodcocks, calves, &c., are fullest in the full of the moon, and so of oysters and cockles, which of all the rest are the easiest tried, if you have them in pits." A few years after Francis Bacon wrote these lines, the Royal Society was founded. Among its first enquiries was the following addressed to travellers to the East Indies : " Whether those shell-fishes, that are in these parts plump and in season at the full moon, and lean and out of season at the new, are found to have contrary con- stitutions in the East Indies ? " This query remained unanswered for two and a half centuries. It has lately been answered by a publication in the Proceedings of the Royal Society, giving the details of the behaviour of the Suez sea-urchin described above.
The most astonishing fact, however, about all of this belief in a lunar effect on shell-fish has yet to be mentioned. Whereas the' Suez urchin actually does spawn at each full moon, the sea-urchins in the Mediterranean do not do so. Nor do the oysters nor any other shell-fish in the Mediterranean, or in our own seas, show any lunar variation in bulk whatever. The moon story is trite of urchins in the Red Sea ; it is untrue of all shell-fish in the Mediterranean.
How then are we to explain the present-day belief all around Mediterranean shores, and how are we to explain the statements of classical and mediaeval authors ? The only reasonable explanation. seems to be that ancient Egypt passed on the statement, true of the Suez urchin, to Greece. The Greeks accepted the statement ex cathedra, and handed it on right down to our own times. This affords an amazing example. of the power of authority in tradition. E. MUNRO Fox?
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