Hints to Travellers, Scientific and General, Vol. 2 / Tenth edition, revised and corrected

by Royal Geographical Society

Collectors of skins should always leave the skull intact. It should be taken out, labelled with a corresponding number to that on the skin, and dried with as much flesh on it as possible.

Reptiles and Fishes.—Full directions for preserving these will be found in the British Museum ‘Handbook,’ pp. 33-47. The following ‘hints’ were prepared by the late Mr. Osbert Salvin, F.R.S., who collected these animals most successfully in Guatemala:—

Almost any spirit will answer for this purpose, its fitness consisting in the amount of alcohol contained in it. In all cases it is best to procure the strongest possible, as it is less bulky, and water can always be obtained to reduce the strength to the requisite amount. When the spirit sold retail by the natives is not sufficiently strong, by visiting the distillery the traveller can often obtain the first runnings (the strongest) of the still, which will be stronger than he requires undiluted. The spirit used should be reduced to about 20° over proof, and the traveller should always be provided with an alcoholometer. If this is not at hand, a little practice will enable him to ascertain the strength of the spirit from the rapidity with which the bubbles break when rising to the surface of a small quantity shaken in a bottle. When the spirit has been used this test is of no value. When reptiles or fish are first immersed, it will be found that the spirit becomes rapidly weaker. Large specimens absorb the alcohol very speedily. The rapidity with which this absorption takes place should be carefully watched, and in warm climates the liquid tested at least every twelve hours, and fresh spirit added to restore it to its original strength. In colder climates it is not requisite to watch so closely, but practice will show what attention is necessary. It will be found that absorption of alcohol will be about proportionate to the rate of decomposition. Spirit should not be used too strong, as its effect is to contract the outer surface, and close the pores, thus preventing the alcohol from penetrating through to the inner parts of the specimen. The principal point, then, is to watch that the strength of the spirit does not get below a certain point while the specimen is absorbing alcohol when first put in. It will be found that after a few days the spirit retains its strength: when this is the case, the specimen will be perfectly preserved. Spirit should not be thrown away, no matter how often used, so long as the traveller has a reserve of sufficient strength to bring it back to its requisite strength.

In selecting specimens for immersion, regard must be paid to the means at the traveller’s disposal. Fishes up to 9 inches long may be placed in spirit, after a slit has been cut in the side of the belly to allow the spirit to enter to the entrails. With larger specimens, it is better to pass a long knife outside the ribs, so as to separate the muscles on each side of the vertebræ. It is also as well to remove as much food from the entrails as possible, taking care to leave all these in. The larger specimens can be skinned, leaving, however, the intestines in, and simply removing the flesh. Very large specimens preserved in this way absorb very little spirit. All half-digested food should be removed from snakes and animals. In spite of these precautions, specimens will often appear to be decomposing; but, by more constant attention to restrengthening the spirit, they can, in most cases, be preserved.

A case (copper is the best), with a top that can be unscrewed and refixed easily, should always be carried as a receptacle. The opening should be large enough to allow the hand to be inserted; this is to hold freshly-caught specimens. When they have become preserved, they can all be removed and soldered up in tin or zinc boxes. Zinc is best, as it does not corrode so easily. The traveller will find it very convenient to take lessons in soldering, and to be able to make his own boxes. If he takes them ready-made, they had best be arranged so as to fit one into another before they are filled. When moving about, all specimens should be wrapped in calico or linen or other rags to prevent their rubbing one against the other. This should also be done to the specimens in the copper case when a move is necessary, as well as to those finally packed for transmission to Europe. These last should have all the interstices between the specimens filled in with cotton-wool or rags. If a leak should occur in a case, specimens thus packed will still be maintained moist, and will keep some time without much injury. Proof spirit should be used when the specimens are finally packed, but it is not necessary that it should be fresh.

Land and Freshwater Mollusca.[14] Full instructions for collecting these will be found in the ‘British Museum Handbook,’ pp. 113-115. Lieut.-Col. H. H. Godwin-Austen, F.R.S., has contributed the following notes on collecting these animals: Mollusca are always most abundant on limestone rocks, and should be searched for under the larger stones lying about the ground, and under fallen trees and logs in the woods and forests. They may generally be found adhering to the surface of the stone or wood. Many species are often only 0.05 inch in length, so that very close examination is necessary. In damp spots, generally in ravines with a northerly aspect, the dead leaves when damp with dew in the early morning may be turned over one by one, and the under surface examined for minute species; larger species will be found very frequently on the surface of the ground below the layer of decaying vegetable matter. Many may also be secured by tearing off the bark of decaying trees. In the drier parts of the country some species are only to be found among the roots of shrubs, at considerable depth; by digging these up and shaking the earth on to paper, small shells may be found on close examination. At a dry place like Aden, I should expect to find most of the living land-shells in such a habitat. Look well in limestone caves on the damp surface of the rock; some forms hide themselves under a coating of earthy matter. Search also on damp moss and rocks near waterfalls.

Some species will be found high up on the bushes and trees. This is the habit of certain African forms especially; not so in India. A very good idea of the land-shells of a country may at first be obtained by the examination of the beds of the streams, either along the highest flood-line, or in the fine sand and mud collected in the bed. Land-shells found in such situations are usually old and bleached, but the living specimens will not be far off.

The leaves and stems of water plants should be examined, and Confervæ taken out of the water and well washed in a basin; in these, and in the mud of ponds and still rivers, many minute shells may be found.

The best way of preserving minute shells is to put them into glass tubes plugged with wool; it is better than cork. Capital collecting tubes can be made out of the smaller sorts of bamboo and the large grasses. A certain number of every species (at least a dozen) should be preserved in spirits for the sake of the anatomy. It is best to kill them first in water and then put them into spirits; if this is not done they contract, so that it is impossible to form any idea of the form of the mantle and other parts, and they become so hard they are difficult to cut up.