29 MARCH 1940, Page 21

Desirable Aliens Fears of any naturalisation experiment are of course

natural and proper. What grim results have ensued from the introduction of the rabbit, fox and blackberry, not to mention the sweet briar, into Australia! In England we have been terrified by the unintentional release of the musk rat ; and most countrymen have regretted the intentional multiplication of little owls from Spain and grey squirrels from the United States. On the other hand, the English Zoo, like the French Jardin d'Acclimatation, were created for the sake of import- ing alien animals and plants. We have not regretted the Mongolian pheasant, and about half our trees in the wild and much more than half in the garden, are wholly desirable aliens. So long as the deed is done by good naturalists, who look well into the nature and habit of the animal or plant they introduce, all should be well, though prophecy is diffi- cult. It is unfortunately not always true to say of squirrel, monkey plant and earwig, for examples, caelum non animum mutant qui trans mare currunt.