But the canal is not less important to the United States from the point of view of giving access between one part of their own vast dominions and another. At the present time there is a very large trade carried on between New York and San Francisco. A great part of that trade now goes overland, in consequence of the time. and cost incurred in sending it by sea. Vessels trading between the two ports are compelled to go round Cape Horn, a distance of some 19,000 miles, whereas, if the Isthmus route were opened, the distance would be reduced to 5,000 miles; in other words, the journey would be shortened by some 14,000 miles. It is quite true that vessels are not very largely employed in this trade at the present time, and that the competition between the various transcontinental railways for the traffic between the Atlantic and the Pacific slopes is such as to give great facilities to commerce, and make it almost independent of the sea. But if the sea journey were made, as it could be made, only some 2,000 miles longer than the railway journey, instead of being, as it now is, about six times as long, there is no saying how the channels and development of the trans-continental traffic may vary and change. Already New York is one of the most important export and import ports in the whole world. The value of the imports into that port in 1886 amounted to not less a sum than $419,500,000, and the exports were as much as $314,500,000, so that the total trade of the port for 1886 was $734,000,000 or 147,000,000l. sterling. This was more than onehalf of the total foreign trade of the United States in the same year. On the Pacific side the trade was little more than a fraction of these figures, the exports from San Francisco amounting to $30,250,000, and the imports to $37,250,000. But there is, in the opinion of the highest authorities, a magnificent future for California. There are even those who predict that the City of the Golden Gates will one day rival New York in the extent of its internal wealth and external commerce. However this may be, San Francisco is the key of the Pacific, and is the threshold of territories of unlimited dimensions, wealth, and natural attractions. It is therefore, of very great importance to the trade and commerce of our own country, as well as of the United States, that by the Panama Canal the distance between London or Liverpool and San Francisco will be shortened by some thousands of miles, while a great part of the western area of British America and the United States, as well as Peru, Mexico, Colombia, and, indeed, the vast territories of South America generally will be brought within much more easy access. The opening up of these territories, and the advancement of their intercourse with the rest of the world, will be infinitely nearer to a consummation when the Cape Horn voyage is no longer necessary to their approach by sea.

If it were given to us to cast the horoscope of the future, we should almost stand appalled at the vast changes that its womb may

hold as the pregnant results of this achievement. At the present time England has the lion's share of the world's trade; and the commerce carried on between England and the United States is larger than that of any other two countries on the face of the globe. It is, however, impossible, in the course of nature, that this supremacy can endure for all time. The old order changes, yielding place to new.' The past was for Greece and Rome, the present is for England, Germany, and France; the future is undoubtedly for those countries that offer facilities for the development of commerce and industry, with which the limited area of Europe and the redundant population of these islands cannot successfully compete. Macaulay's New Zealander will not in our time be found sitting on a broken arch of London Bridge, while he sketches the ruins of St. Paul's. But that time is not unlikely to come in the long run. England has not found any elixir of life whereby she is to flourish in immortal youth.' The battle of the future must be to the strong, and the time is not likely to be far off when the sceptre of empire, of commerce, of wealth, and of industry, will be largely, if not wholly, transferred to those countries which are to be joined together by one or other of the water-ways that are now being projected across the American isthmus.

J. STEPHEN JEANS.

A COUNTER CRITICISM.

WHILE I do not concur in sundry of the statements and conclusions contained in the article entitled 'A Great Confession,' contributed by the Duke of Argyll to the last number of this Review, yet I am obliged to him for having raised afresh the question discussed in it. Though the injunction Rest and be thankful,' is one for which in many spheres much may be said—especially in the political, where undue restlessness is proving very mischievous-yet rest and be thankful is an injunction out of place in science. Unhappily, while politicians have not duly regarded it, it appears to have been taken to heart too much by naturalists; in so far, at least, as concerns the question of the origin of species.

The new biological orthodoxy behaves just as the old biological orthodoxy did. In the days before Darwin, those who occupied themselves with the phenomena of life passed by with unobservant eyes the multitudinous facts which point to an evolutionary origin for plants and animals; and they turned deaf ears to those who insisted upon the significance of these facts. Now that they have come to believe in this evolutionary origin, and have at the same time accepted the hypothesis that natural selection has been the sole cause of the evolution, they are similarly unobservant of the multitudinous facts which cannot rationally be ascribed to that cause; and turn deaf ears to those who would draw their attention to them. The attitude is the same; it is only the creed which has changed.

But, as above implied, though the protest of the Duke of Argyll against this attitude is quite justifiable, it seems to me that many of nis statements cannot be sustained. Some of these concern me personally, and others are of impersonal concern. I propose to deal with them in the order in which they occur.

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On page 144 the Duke of Argyll quotes me as omitting for the present any consideration of a factor which may be distinguished as primordial;' and he represents me as implying by this that Darwin's ultimate conception of some primordial "breathing of the breath of life" is a conception which can only be omitted" for the present." Even had there been no other obvious interpretation, it would have been a somewhat rash assumption that this was my meaning when

referring to an omitted factor; and it is surprising that this assumption should have been made after reading the second of the two articles criticised, in which this factor omitted from the first is dealt with this omitted third factor being the direct physico-chemical action of the medium on the organism. Such a thought as that which the Duke of Argyll ascribes to me, is so incongruous with the beliefs I have in many places expressed that the ascription of it never occurred to me as possible.

Lower down on the same page are some other sentences having personal implications, which I must dispose of before going into the general question. The Duke says 'it is more than doubtful whether any value attaches to the new factor with which he [I] desires to supplement it '[natural selection]; and he thinks it unaccountable 'that I' should make so great a fuss about so small a matter as the effect of use and disuse of particular organs as a separate and a newly reccgnised factor in the development of varieties.' I do not suppose that the Duke of Argyll intended to cast upon me the disagreeable imputation, that I claim as new that which all who are even slightly acquainted with the facts know to be anything rather than new. But his words certainly do this. How he should have thus written in spite of the extensive knowledge of the matter which he evidently has, and how he should have thus written in presence of the evidence contained in the articles he criticises, I cannot understand. Naturalists, and multitudes besides naturalists, know that the hypothesis which I am represented as putting forward as new is much older than the hypothesis of natural selection-goes back at least as far as Dr. Erasmus Darwin. My purpose was to bring into the foreground again a factor which has, I think, been of late years improperly ignored; to show that Mr. Darwin recognised this factor in an increasing degree as he grew older (by showing which I should have thought I sufficiently excluded the supposition that I brought it forward as new); to give further evidence that this factor is in operation; to show there are numerous phenomena which cannot be interpreted without it; and to argue that if proved operative in any cases, it may be inferred that it is operative on all structures having active functions.

Strangely enough, this passage in which I am represented as implying novelty in a doctrine which I have merely sought to emphasize and extend, is immediately succeeded by a passage in which the Duke of Argyll himself represents the doctrine as being familiar and well established:

That organs thus enfeebled [i.e. by persistent disuse] are transmitted by inheritance to offspring in a like condition of functional and structural decline, is a correlated physiological doctrine not generally disputed. The converse case—of increased strength and development arising out of the habitual and healthy use of special organs, and of the transmission of these to offspring is a case illustrated by many examples in the breeding of domestic animals. I do not know to what else we can attribute the long slender legs and bodies of greyhounds so manifestly adapted to

speed of foot, or the delicate powers of smell in pointers and setters, or a dozen cases of modified structure effected by artificial selection.

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In none of the assertions contained in this passage can I agree. Had the inheritance of functional and structural decline' been not generally disputed,' half my argument would have been needless; and had the inheritance of increased strength and development' caused by use been recognised, as illustrated by many examples,' the other half of my argument would have been needless. But both are disputed; and, if not positively denied, are held to be unproved. Greyhounds and pointers do not yield valid evidence, because their peculiarities are more due to artificial selection than to any other cause. It may, indeed, be doubted whether greyhounds use their legs more than other dogs. Dogs of all kinds are daily in the habit of running about and chasing one another at the top of their speed -other dogs more frequently than greyhounds, which are not much given to play. The occasions on which greyhounds exercise their legs in chasing hares occupy but inconsiderable spaces in their lives, and can play but small parts in developing their legs. And then, how about their long heads and sharp noses? Are these developed by running? The structure of the greyhound is explicable as a result mainly of selection of variations occasionally arising from unknown causes; but it is inexplicable otherwise. Still more obviously invalid is the evidence said to be furnished by pointers and setters. How can these be said to exercise their organs of smell more than other dogs? Do not all dogs occupy themselves in sniffing about here and there all day long: tracing animals of their own kind and of other kinds? Instead of admitting that the olfactory sense is more exercised in pointers and setters than in other dogs, it might, contrariwise, be contended that it is exercised less; seeing that during the greater parts of their lives they are shut up in kennels where the variety of odours, on which to practise their noses, is but small. Clearly if breeders of sporting dogs have from early days habitually bred from those puppies of each litter which had the keenest noses (and it is undeniable that the puppies of each litter are made different from one another, as are the children in each human family, by unknown combinations of causes), then the existence of such remarkable powers in pointers and setters may be accounted for; while it is otherwise unaccountable. These instances, and many others such, I should have gladly used in support of my argument had they been available; but unfortunately they are not.

On the next page of the Duke of Argyll's article (page 145), occurs a passage which I must quote at length before I can deal effectually with its various statements. It runs as follows::

But if natural selection is a mere phrase, vague enough and wide enough to cover any number of the physical causes concerned in ordinary generation, then the whole of Mr. Spencer's laborious argument in favour of his other factor' VOL. XXIII.-No. 132.

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