Part 14 (1/2)

With the exception of the orange, the fruits of Ceylon have one deficiency, common, I apprehend, to all tropical countries. They are wanting in that piquancy which in northern climates is attributable to the exquisite perfection in which the sweet and aromatic flavours are blended with the acidulous. Either the acid is so ascendant as to be repulsive to the European palate, or the saccharine so preponderates as to render Singhalese fruit cloying and distasteful.

Still, all other defects are compensated by the coolness which pervades them; and, under the exhaustion of a blazing sun, no more exquisite physical enjoyment can be imagined than the chill and fragrant flesh of the pine-apple, or the abundant juice of the mango, which, when freshly pulled, feels as cool as iced water. But the fruit must be eaten instantly; even an interval of a few minutes after it has been gathered is sufficient to destroy the charm; for, once severed from the stem, it rapidly acquires the temperature of the surrounding air.

Sufficient admiration has hardly been bestowed upon the marvellous power displayed by the vegetable world in adjusting its own temperature, notwithstanding atmospheric fluctuations,--a faculty in the manifestation of which it appears to present a counterpart to that exhibited by animal oeconomy in regulating its heat. So uniform is the exercise of the latter faculty in man and the higher animals, that there is barely a difference of three degrees between the warmth of the body in the utmost endurable vicissitudes of heat and cold; and in vegetables an equivalent arrangement enables them in winter to keep their temperature somewhat above that of the surrounding air, and in summer to reduce it far below it. It would almost seem as if plants possessed a power of producing cold a.n.a.logous to that exhibited by animals in producing heat; and of this beneficent arrangement man enjoys the benefit in the luxurious coolness of the fruit which nature lavishes on the tropics.

The peculiar organisation by which this result is obtained is not free from obscurity, but in all probability the means of adjusting the temperature of plants is simply dependent on evaporation. As regards the power possessed by vegetables of generating heat, although it has been demonstrated to exist, it is in so trifling a degree as to be almost inappreciable, except at the period of germination, when it probably arises from the consumption of oxygen in generating the carbonic acid gas which is then evolved. The faculty of retaining this warmth at night and at other times may, therefore, be referable mainly to the closing of the pores, and the consequent check of evaporation.

On the other hand, the faculty of maintaining a temperature below that of the surrounding air, can only be accounted for by referring it to the mechanical process of imbibing a continuous supply of fresh moisture from the soil, the active transpiration of which imparts coolness to every portion of the tree and its fruit. It requires this combined operation to produce the desired result; and the extent to which evaporation can bring down the temperature of the moisture received by absorption, may be inferred from the fact that Dr. Hooker, when in the valley of the Ganges, found the fresh milky juice of the Mudar (_calotropis_) to be but 72, whilst the damp sand in the bed of the river where it grew was from 90 to 104.

Even in temperate climates this phenomenon is calculated to excite admiration; but it is still more striking to find the like effect rather increased than diminished in the tropics, where one would suppose that the juices, especially of a small and delicate plant, before they could be cooled by evaporation, would be liable to be heated by the blazing sun.

A difficulty would also seem to present itself in the instance of fruit, whose juices, having to undergo a chemical change, their circulation would be conjectured to be slower; and in the instance of those with hard skins, such as the pomegranate, or with a tough leathery coating, like the mango, the evaporation might be imagined to be less than in those of a soft and spongy texture. But all share alike in the general coolness of the plant, so long as circulation supplies fluid for evaporation; and the moment this resource is cut off by the separation of the fruit from the tree, the supply of moisture failing, the process of refrigeration is arrested, and the charm of agreeable freshness gone.

It only remains to notice the aquatic plants, which are found in greater profusion in the northern and eastern provinces than in any other districts of the island, owing to the innumerable tanks and neglected watercourses which cover the whole surface of this once productive province, but which now only harbour the alligator, or satisfy the thirst of the deer and the elephant.

[Footnote 1: See on this subject LINDLEY'S _Introduction to Botany_, vol. ii. book ii. ch. viii. p. 215.

CARPENTER, _Animal Physiology_, ch. ix. s. 407. CARPENTER'S _Vegetable Physiology_, ch. xi. s. 407, Lond. 1848.]

The chief ornaments of these neglected sheets of water are the large red and white Lotus[1], whose flowers may be seen from a great distance reposing on their broad green leaves. In China and some parts of India the black seeds of these plants, which are not unlike little acorns in shape, are served at table in place of almonds, which they are said to resemble, but with a superior delicacy of flavour. At some of the tanks where the lotus grows in profusion in Ceylon, I tasted the seeds enclosed in the torus of the flowers, and found them white and delicately-flavoured, not unlike the small kernel of the pine cone of the Apennines. This red lotus of the island appears to be the one that Herodotus describes as abounding in the Nile in his time, but which is now extinct; with a flower resembling a rose, and a fruit in shape like a wasp's nest, and containing seeds of the size of an olive stone, and of an agreeable flavour.[2] But it has clearly no ident.i.ty with those which he describes as the food of the Lotophagi of Africa, of the size of the mastic[3], sweet as a date, and capable of being made into wine.

[Footnote 1: Nelumbium speciosum.]

[Footnote 2: Herodotus, b. ii. s. 92.]

[Footnote 3: The words are ”[Greek: Esti megathos hoson te tes schinou]”

(Herod. b. iv. s. 177); and as [Greek: schinos] means also a _squill_ or a _sea-onion_, the fruit above referred to, as the food of the Lotophagi, must have been of infinitely larger size and in every way different from the lotus of the Nile, described in the 2nd book, as well as from the lotus in the East. Lindley records the conjecture that the article referred to by Herodotus was the _nabk_, the berry of the lote-bush (_Zizyphus lotus_), which the Arabs of Barbary still eat.

(_Vegetable Kingdom_, p. 582.)]

One species of the water lily, the _Nymphaea rubra_, with small red flowers, and of great beauty, is common in the ponds near Jaffna and in the Wanny; and I found in the fosse, near the fort of Moeletivoe, the beautiful blue lotus, _N. stellata_, with lilac petals, approaching to purple in the centre, which had not previously been supposed to be a native of the island.

Another very interesting aquatic plant, which was discovered by Dr.

Gardner in the tanks north of Trincomalie, is the _Desmanthus natans_, with highly sensitive leaves floating on the surface of the water. It is borne aloft by ma.s.ses of a spongy cellular substance, which occur at intervals along its stem and branches, but the roots never touch the bottom, absorbing nourishment whilst floating at liberty, and only found in contact with the ground after the subsidence of water in the tanks.[1]

[Footnote 1: A species of _Utricularia_, with yellow flowers (U.

stellaris), is a common water-plant in the still lakes near the fort of Colombo, where an opportunity is afforded of observing the extraordinary provision of nature for its reproduction. There are small appendages attached to the roots, which become distended with air, and thus carry the plant aloft to the surface, during the cool season. Here it floats till the operation of flowering is over, when the vesicles burst, and by its own weight it returns to the bottom of the lake to ripen its seeds and deposit them in the soil; after which the air vessels again fill, and again it re-ascends to undergo the same process of fecundation.]

PART II.

ZOOLOGY.

CHAPTER I.

MAMMALIA.

With the exception of the Mammalia and the Birds, the fauna of Ceylon has, up to the present, failed to receive that systematic attention to which its richness and variety so amply ent.i.tle it. The Singhalese themselves, habitually indolent and singularly un.o.bservant of nature in her operations, are at the same time restrained from the study of natural history by tenets of their religion which forbid the taking of life under any circ.u.mstances. From the nature of their avocations, the majority of the European residents engaged in planting and commerce, are discouraged from gratifying this taste; and it is to be regretted that the civil servants of the government, whose position and duties would have afforded them influence and extended opportunity for successful investigation, have never seen the importance of encouraging such studies.

The first effective impulse to the cultivation of natural science in Ceylon, was communicated by Dr. Davy when connected with the medical staff of the army from 1816 to 1820, and his example stimulated some of the a.s.sistant surgeons of Her Majesty's forces to make collections in ill.u.s.tration of the productions of the colony. Of the late Dr. Kinnis was one of the most energetic and successful. He was seconded by Dr.