590 



SCIENTIFIC NEWS. 



[June 22, li 



character, excepting, of course, as regards the marsupial 

 structure, and was fully equal in size to the existing 

 African species. 



Similar discoveries have also been made in Victoria 

 from post-pleiocene deposits ; and it is worthy of note 

 that, many years ago, Professor Owen, in commenting 

 upon the herbivorous characteristics of the extinct 

 Australian diprotodon, expressed a strong conviction that 

 some large carnivoron must have been contemporary 

 with it, in order to restrain its numbers within due 

 bounds. Now that these remains have been found, no 

 doubt whatever remains upon the subject, and we have 

 certain testimony that at an earlier period of the world's 

 history a lion-like mammal was numbered among the 

 Australian /«;/««, and thus that the great and important 

 family of the cats was represented by one ot those 

 feebler imitations of which, mimicking animals of 

 different kinds, we find so many still existing. 



The question naturally arises, How did these em- 

 bryotic types, so to speak, originate, and how is it that 

 they have risen no higher ? Why are there not a cat 

 tribe and a dog tribe in Australia, just as there are in 

 other continents ? Why does nature seem to have 

 stopped short, so to speak, in the work of evolution in 

 one part of the world, while carrying it on in another ? 



An answer, although, perhaps, not a perfectly conclu- 

 sive one, is not far to seek. 



We have, in the first place, to remember, as Mr. 

 Darwin has shown us, that competition between different 

 animals has much to answer for in the gradual evolving 

 of the higher type from the lower. The fiercer and more 

 incessant the struggle for existence, the more searching 

 will be the natural selection appointing the individuals 

 which are to survive. And the degree of this competition 

 depends very largely upon the area which the animals in 

 question inhabit. With an extended area comes a cor- 

 responding extension in the number both of species and 

 of individuals, which must struggle for the mastery ; 

 with a limited area comes a corresponding diminution. 

 And how important a factor is this in bringing about 

 final results, no reader of the " Origin of Species" can be 

 ignorant. 



Now in the case of the Australian fauna the struggle 

 for existence can never have been especially severe, 

 owing to the small size of the continent, and also to the 

 limited number of the animals which inhabit it. Of the 

 three continents into which the land of our globe is divided 

 — for Europe, Asia, and Africa are all one, just as 

 North and South America are another— Australia is very 

 much the least, and the competition between the animals 

 to which she affords a home can at no time have been 

 very keen. The largest and strongest animals of all we 

 find in the largest continent; the smallest and weakest in 

 the least. And America is midway between the two, 

 producing a varied and extensive fauna, but without either 

 the large and powerful species of the former, or the weak 

 and feeble creatures of the latter. The elephant, the 

 rhinoceros, the hippopotamus, the giraffe, the lion, the 

 tiger, and the ostrich : all these are African or Asiatic. 

 America is the home of the bison, the puma, the jaguar, 

 and the rhea ; smaller and less powerful. And in 

 Australia we have nothing larger than the kangaroo and 

 the emu, both of which are physically inferior to animals 

 of equal size inhabiting the other continents. 



Thus it would seem that the inferiority of the"Australian 

 mammals is largely due to the small size and the isolated 

 position of their native land. They have not been com- 



pelled to pass through long periods of severe competition, 

 and so have stood still while other animals have advanced, 

 evolution being rendered a iar more tedious process than 

 if surrounding conditions had been more favourable. 

 Not only that, their physical powers are less developed, 

 their robustness and endurance less great, than in animals 

 of lesser size, reared under circumstances more suitable 

 for the development of constitutional vigour. Thus it is 

 that such mammals, birds, and even plants, as we have 

 introduced into Australia have carried all before them, 

 and increased and multiplied to a degree which we never 

 for a moment anticipated. The rabbit, the sparrow, the 

 sweet-briar and the thistle, all these have broken bounds 

 altogether, and are steadily pushing their way with 

 resistless pertinacity towards the districts which they do 

 not at present occupy. Their robust nature, tried and 

 proved by many centuries of competition, enables them 

 without difficulty to oust and overcome others which have 

 not been subjected to an ordeal of equal severity, and 

 thus it is that these introduced animals and plants con- 

 tinue their irresistible advance, overcoming and expelling 

 others of greater size and apparently more perfect con- 

 stitution. 



As far as the strictly marsupial character of the 

 Australian mammals is concerned, other causes have no 

 doubt been at work, of which we know little or nothing, 

 for it is not suggested that the quadrumana, carnivora, 

 rodents, and ungulates of other parts of the world have 

 sprung from similar parentage. But it is, to say the 

 least, strongly suggestive to find, as it were, the germs 

 of many of these orders among the marsupial mammals, 

 and it is difficult to refrain from speculation upon the 

 results which might have followed had these animals 

 been placed from the first under conditions similar to 

 those encompassing others. Probably they would have 

 developed in very much the same degree; certainly they 

 would have attained to forms very dift'erent from those 

 in which we see them now. And more than this, in the 

 present state of our knowledge, it is unfortunately quite 

 impossible to say. 



The Reason Why. London : Houlston and Sons. 1888. 

 This book professes to contain " a careful collection of 

 many hundreds of reasons for things which, though 

 generally believed, are imperfectly understood " ; and on 

 its title-page it bears, besides the above announcement 

 and the imposing words General Science, an intimation 

 that it has reached its fifty-third thousand. We are sin- 

 cerely sorry to hear it, for we have never seen any work 

 of the kind displaying more ignorance on the part of its 

 compiler, or better calculated to give false and inaccurate 

 ideas to its readers. This is a grave accusation, but we 

 are quite prepared to substantiate it by extracts and 

 references. On page 4 the reader is told that light, heat, 

 and electricity are called "imponderable elements " because 

 they " differ from other elements in being destitute of 

 weight," and on the next page that " the imponderable " 

 is " a state of matter," and that " there are various 

 opinions as to whether light, heat, and electricity are 

 substances." Chapter VI. takes us back to the dark ages 

 in physics ; therein we find " caloric " spoken of as being 

 " squeezed or forced out " of bodies when struck against 

 one another, and the inquirer is assured that if flint and 

 steel were soft and yielding, " the caloric would simply 



