of nomadic tribes, which, living as they did in tents, originated the conception.1

On the other changes very time does it

Among peoples where the system of marriage by groups has existed, family nomenclatures continued to persist long after the disappearance of the family system to which they owed their origin. 'The family," says Morgan, "is an active element, never stationary; it keeps pace with the development of society in the march of progress. hand, the reckoning of kinship slowly; only after long lapses of register the progress actually made by the family in the course of ages, and does not undergo any radical transformation until long after the family itself has been completely changed." "And," adds Karl Marx, whose critical annotations on Morgan's book were carefully preserved by Engels, "this also applies to systems of politics, law, religion, or philosophy."

These systems, formed after the completion of the social organization which they express, survive after the organization itself has disappeared. Their elimination is not of such importance to society as is that of the economic or family institutions themselves, as these, when they become useless and disadvantageous, are a drag on future development. 1 Viollet, Histoire du droit civil fr., p. 617.

"Although houses were for centuries treated as moveable property, they continued to be legally treated as such for a still longer period of time; it is characteristic of judicial ideas that they lag far behind economic progress."

It cannot be established, however, as a general principle, that the pathway of degeneration as regards societies or institutions, is inverse to that pursued by their progressive evolution. In the first place, the mere explanation of this supposed law shows that it is quite untenable.

What reason is given for supposing the decline of memory or will power, the degeneration of writing and speech, the decadence of societies and institutions, to be a retracing of the steps of progressive development ? The reason given is that, other things being equal, the more fragile, unsteady and complicated structures are the first to fall.

Now, although the most fragile structures are frequently those most recently formed, and which have not had time to settle down and firmly establish themselves, it is also true that in many cases the more recent acquisitions and structures attain a more solid basis than those which have preceded them.

There is nothing invariable about the pathway of degeneration. It can no more be said to retrace the pathway of progress in an inverse direction than it could be said that in a country abandoned by its inhabitants the more recently formed paths of communication would be the first to become effaced. It is quite true that the broader roads, which would naturally last longer, are frequently the oldest paths of communication; whereas the footpaths,

which are the first to disappear, are usually of more recent origin. Very frequently, however, the new roads follow a rather different direction, and, although more recently constructed, are not the first to disappear.

It

It is the same with great commercial crises. is quite inexact to say with Ribot, who is responsible for the analogy: "Old houses offer the best resistance to the storm; it is the new houses which, being less solid, crumble and fall." 1

After the time of the cotton famine, during the American war of Independence, the greater part of the old firms of Gand became bankrupt, whereas most of the large, newly-established joint-stock companies survived the crisis.

Moreover, in those cases where the most recently formed structures are the first to decay, it cannot be deduced that evolution is reversed, and that the institution returns to its primitive condition, for there is no reappearance of the intermediate structures.

1 Ribot, Les Maladies de la Memoire, p. 99.

PART II

The irreversibility of degenerative evolution

MOST authorities on the subject are agreed that evolution is not reversible, and that institutions or organs which have disappeared or been reduced to rudiments do not reappear and develop afresh. It would be a useless extension of this volume to cite many facts in favour of a view which is almost without supporters, but it will be useful to examine the exceptions, real or apparent, and to discuss

1. If an institution or organ which has disappeared may reappear.

2. If an institution or organ which has been

reduced may resume its primitive function. 3. If an institution or organ which has been reduced may redevelop and assume a function other than its original function.

1 L. Dollo, Les lois de l'Évolution (Soc. Belg. Géol. Paléont. Hydr., t. vii., 1893, procès-verbaux, pp. 164-166.

CHAPTER I

DO INSTITUTIONS OR ORGANS WHICH HAVE DISAPPEARED REAPPEAR?

SECTION I

Disappeared organs

IN biology we are almost unaware of indisputable examples of the normal reappearance of disappeared

organs.

1. Plants. As the embryonic development of plants is usually direct, it is impossible to decide whether an organ which forms a component part of the embryological history represents an ancestral organ. However, in a few rare cases, artificial selection causes an actual reversion of evolution. Typical geraniums possess two whorls of five stamens, as, for instance, in Geranium. In Erodium there is only one cycle of five. In Pelargonium one cycle of five is complete; the other is represented by two stamens and three filaments which have lost their anthers. But in certain varieties with very large flowers the two complete cycles reappear, five stamens having long, and five short, filaments. In this case there is no doubt as to the reappearance of the three stamens lost in typical Pelargoniums.