294 



SCIENTIFIC NEW^S. 



[Mar. 30, lE 



practice come to have a very different meaning from that 

 which its etymology would show. As generally used it 

 means the introduction of any alien plant or animal into 

 a country by human agency. Whether such immigrants 

 had to be gradually adapted to their new home by a 

 series of physiological modifications, or whether they at 

 once found it equally congenial with their mother 

 country, or perhaps even more so, is not here the 

 question. 



Another glance at the word may still be useful. It 

 seems to imply that the main reason why any animal or 

 plant flourishes in one country but perishes in another is 

 some difference in the climate, in the ordinary geo- 

 graphical sense of that word. That is, it conveys 

 the impression that the fauna and flora of a country 

 depend solely upon its mean or its extreme temperature 

 at different seasons or for the entire year, upon its degree 

 or distribution of moisture, or upon atmospheric pressure. 

 Now without overlooking the influence of these physical 

 conditions of life we must remember that they are not 

 the sole agencies in determining what species shall live 

 in any given region. There are good physical reasons 

 why humming-birds are not found in Iceland, Greenland, 

 or Siberia. There are no such reasons manifest why 

 they might not flourish in Madagascar, in Borneo, or New 

 Guinea, as well as in Guatemala or Brazil. 



It was said above " the introduction of a living species 

 through human agency." We might have added " inten- 

 tional or accidental." It will not be supposed that man 

 has knowingly and of set purpose selected as his com- 

 panions those living beings which have accompanied him 

 in his wanderings. Far from it : as proof to the contrary 

 we need merely mention the cockroach and the grey rat, 

 — Norwegian of earlier writers, Hanoverian of Charles 

 Waterton, but more truthfully and more significantly 

 Russian ! Man would no more wilfully acclimatise such 

 pests than he would the small-pox or the cholera. 



It is often thought that acclimatisation is promoted 

 and recommended by scientific men. Such is by no means 

 the case. The genuine zoologist or botanist looks upon 

 the introduction of alien species in a feral state into any 

 country with as little approval as the classical scholar 

 regards the interpolation of spurious passages in some 

 ancient author. Even in Britain doubts have already 

 arisen whether certain plants are truly native or whether 

 they have been artificially introduced. That the con- 

 sequences of the artificial immigration of plants and 

 animals may teach us valuable biological lessons is 

 admitted. But none of us would have made the experi- 

 ment. No scientific man, from the highest to the lowest, 

 would have carried goats to St. Helena or the Cape, 

 rabbits to Australia, or white cabbage-butterflies to 

 America merely to see what would happen. 



We must remember that acclimatisation is a very 

 serious thing ; far too grave to be left to the indiscretion 

 of ignorant and careless individuals. Even the extir- 

 pation of existing forms of animal and plant-life is a task 

 which ought not to be undertaken with a light heart and 

 without well counting the cost. But the risk in intro- 

 ducing some alien species is tenfold graver ; the step if 

 once taken may prove, as far as man's present resources 

 are concerned, beyond recall, and the consequences can- 

 not be in the least foreseen. Of this we shall find some 

 warning examples. 



Perhaps the first lesson to be learnt from our present 

 experience in acclimatisation is the baselessness of one of 

 , the dogmas of the Old School of Natural History. It 



was formerly taught that the plants and the animals of 

 any given country were especially adapted to the soil, 

 the climate, and all other conditions of that locality. It 

 was believed that if transplanted to any other country 

 they would be less prosperous than in their original 

 home, whilst conversely, species brought from elsewhere 

 would maintain their ground with difficulty if at all. 



There are, indeed, many cases where plants and 

 animals, the former more especially, seem limited to 

 their original locality. Thus the durrian and the 

 mangosteen of the Malay Islands do not succeed well 

 even in Ceylon and on the mainland of India, and utterly 

 fail in the West Indies. The shaddocks of the Azores 

 and the Antilles are " flavourless as turnips if compared 

 with those of Bangkok or Labuan." 



But there are no less signal instances to the contrary. 

 The thistle madly brought from Scotland to Australia 

 grows there with a fell luxuriance quite unknown in its 

 native soil. Even the sweet-brier, which is nowhere 

 exceedingly common or rampant in Britain, is becoming 

 in New South Wales a serious nuisance, which the 

 farmer and the gardener are obliged actively to 

 combat. 



Nor are these exceptional cases even among plants. 

 With animals the case is even more striking. The rat 

 multiplies in every corner of the globe where it has 

 penetrated no less readily than in its original home on the 

 Volga. The rabbit, criminally turned loose in Australia, 

 has proved itself an unlimited curse. The sparrow, 

 accliniatised in the United States, in Australia, and in 

 New Zealand, contrary to the advice of judicious 

 European naturalists, has not only established itself but 

 is seriously interfering with the native bird-population. 

 It is certain that the cockroach or " black-beetle " of un- 

 scientific insect-lore is not indigenous in Britain. It is 

 equally certain that its extirpation is one of the mo.st un- 

 lilvely events conceivable. Blood-sucking gnats, accord- 

 ing to Baron Osten-Sacken, were only introduced into the 

 Sandwich Islands about 1828 to 1830 : they have since 

 spread and are becoming a serious nuisance. Tlie same 

 eminent authority states (Trans. Enfom. Soc. of London, 

 1884, p. 492) that the two-winged insects popularly 

 "lumped" together as house-flies "have been imported 

 into Chili, Australia, and New Zealand, where they were 

 not indigenous," and where, it may be added, they are 

 multiplying and growing truly formidable. The United 

 States, even, seem to have been originally free from this 

 plague. Hence it may be safely said that the aboriginal 

 plants and animals of any country are by no means 

 necessarily confined to that country, but that when 

 intentionally transported elsewhere they may flourish 

 as well as, perhaps even better than, at home. 



(To be continued.) 



Gum Arabic. — A substitute for this substance, patented 

 in Germany, is made as follows : — Twenty parts of powdered 

 sugar are boiled with 7 parts of fresh milk, and this is then 

 mixed with 50 parts of a 36 per cent, solution of silicate of 

 sodium, the mixture being then cooledito 122° Fahr. and poured 

 into tin boxes, where granular rhasses will gradually separate 

 out, which look very much like pieces of gum arable. This 

 artificial gum copiously and instantly reduces Fehling's 

 solution, so that if mixed with powdered gum arabic as an 

 adulterant, its presence could be easily detected. The 

 presence of silicate of sodium in the ash would also confirm 

 the presence of adulteration. 



