This operation may be seen in the lowlands, traversed by the high road leading from Colombo to Kandy. Before the change of the monsoon, the hollows on either side of the highway are covered with dust or stunted grass; but when flooded by the rains, they are immediately resorted to by the peasants with baskets, constructed precisely as Knox has stated, in which the fish are entrapped and taken out by the hand.[3411]
So singular a phenomenon as the sudden re-appearance of full-grown fishes in places that a few days before had been encrusted with hardened clay, has not failed to attract attention; but the European residents have been content to explain it by hazarding conjectures, either that the spawn must have lain imbedded in the dried earth till released by the rains, or that the fish, so unexpectedly discovered, fall from the clouds during the deluge of the monsoon.
As to the latter conjecture; the fall of fish during showers, even were it not so problematical in theory, is too rare an event to account for the punctual appearance of those found in the rice-fields, at stated periods of the year. Both at Galle and Colombo in the south-west monsoon, fish are popularly believed to have fallen from the clouds during violent showers, but those found on the occasions that give rise to this belief, consist of the smallest fry, such as could be caught up by waterspouts, and vortices analogous to them, or otherwise blown on shore from the surf; whereas those which suddenly appear in the replenished tanks and in the hollows which they overflow, are mature and well-grown fish.[3421] Besides, the latter are found, under the circumstances I have described, in all parts of the interior, whilst the prodigy of a supposed fall of fish from the sky has been noticed, I apprehend, only in the vicinity of the sea, or of some inland water.
The surmise of the buried spawn is one sanctioned by the very highest authority. Mr. Yarrell in his "History of British Fishes," adverting to the fact that ponds (in India) which had been previously converted into hardened mud, are replenished with small fish in a very few days after the commencement of each rainy season, offers this solution of the problem as probably the true one: "The impregnated ova of the fish of one rainy season are left unhatched in the mud through the dry season, and from their low state of organisation as ova, the vitality is preserved till the recurrence, and contact of the rain and oxygen in the next wet season, when vivification takes place from their joint influence."[3431]
This hypothesis, however, appears to have been advanced upon imperfect data; for although some fish, like the salmon, scrape grooves in the sand and place their spawn in inequalities and fissures; yet as a general rule spawn is deposited not beneath but on the surface of the ground or sand over which the water flows, the adhesive nature of each egg supplying the means of attachment. But in the Ceylon tanks not only is the surface of the soil dried to dust after the evaporation of the water, but earth itself, twelve or eighteen inches deep, is converted into sun-burnt clay, in which, although the eggs of mollusca, in their calcareous covering, are in some instances preserved, it would appear to be as impossible for the ova of fish to be kept from decomposition as for the fish themselves to sustain life. Besides, moisture in such situations is only to be found at a depth to which spawn could not be conveyed by the parent fish, by any means with which we are yet acquainted.
But supposing it possible to carry the spawn sufficiently deep, and to deposit it safely in the mud below, which is still damp, whence it could be liberated on the return of the rains, a considerable interval would still be necessary after the replenishing of the ponds with water to admit of vivification and growth. Yet so far from this interval being allowed to elapse, the rains have no sooner fallen than the taking of the fish commences, and those captured by the natives in wicker cages are mature and full grown instead of being "small fish" or fry, as supposed by Mr. Yarrell.
Even admitting the soundness of his theory, and the probability that, under favourable circumstances, the spawn in the tanks might be preserved during the dry season so as to contribute to the perpetuation of their breed, the fact is no longer doubtful, that adult fish in Ceylon, like some of those that inhabit similar waters both in the New and Old World, have been endowed by the Creator with the singular faculty of providing against the periodical droughts either by journeying overland in search of still unexhausted water, or, on its utter disappearance, by burying themselves in the mud to await the return of the rains.