tance; but were there no profiting by experience most of the shots would go wide. Parental care might be here symbolized by supposing the raw beginner protected and instructed by an expert shot until the necessary experience had been acquired.

We do not know how far down in the scale of animal life some sort of consciousness exists, but the dawn of intelligence is marked by the appearance of what Lloyd Morgan calls "effective consciousness", i.e. a realization of existence which enables more or less successful adjustments to a changing environment.

In ourselves we find Intelligence reinforced by Reason, the "ideational stage" in mental evolution, where actions depend upon motive, instead of being due to mere impulse dictating certain sorts of behaviour "on the spur of the moment". It involves appreciation of abstract ideas with powers of reflection and deliberation, leading us to trace the relations between cause and effect, and to construct ideals of existence by which our conduct is more or less regulated. The dim beginnings of Reason are probably to be found among the higher animals, but the body of facts with which we are at present acquainted is far too small to justify positive statements or wide-sweeping generalizations.

INSTINCT AND INTELLIGENCE IN HIGHER INVERTEBRATES (INVERTEBRATA)

The most instructive cases so far investigated are to be found among Insects (Insecta) and Molluscs (Mollusca), and it will be enough for our present purpose to briefly describe a few of these.

INSTINCT AND INTELLIGENCE IN INSECTS (INSECTA). A good example of the stereotyped nature of complex instincts is given by Fabre (in Souvenirs entomologiques) in his account of one of the Mason-Bees (Chalicodoma muraria) native to South Europe. The female makes a nest consisting of nine or ten cells placed one on top of the other, using cement made of a mixture of earth and saliva, to which little stones are added. After each cell is built it is stored with honey and pollen, after which an egg is laid in it, and a roof is added. The entire series is then thickly covered with cement till the nest assumes a hemispherical form. The three operations of building, storing, and egg-laying which take place in regard to each cell follow one another with automatic regularity, and there is no harking back to an earlier stage. For conditions

artificially imposed with a view to altering the order do not succeed in this, as they would do if the actions were of very intelligent kind. For example, a nest with fully-constructed top-cell partly stored was substituted for the original nest in which the uppermost cell had only been commenced. The bee did not apparently detect the imposture, and proceeded to raise the walls of the substituted cell till it was one-third greater than the normal height. In another experiment a bee had completed the construction of a cell, and was preparing to store it, when another nest with an incomplete top-chamber was substituted. On her return with honey and pollen she appeared greatly puzzled at the change, and finally deposited her load in the nest of a neighbour. The result of another similar experiment was somewhat different, for the bee removed the roof of the last complete cell and stored this a second time, afterwards laying a second egg in it. The last two experiments seem to prove the existence of a certain infusion of intelligence, as shown by the attempts to meet the altered circumstances, though these attempts were not of very satisfactory kind. It is somewhat remarkable that this bee is apparently unable to recognize its own nest, though we must not forget that its visual powers are of different kind from our own, but it has a well-marked memory for localities, returning to the spot selected for buildingpurposes from considerable distances. Fabre also showed that individuals removed as far as four kilometres from their nests, into what was probably unknown country to them, were able to find their way home. Quite a number of animals are endowed with a strong "homing faculty" of this kind, but how far this may be due to a "locality sense which cannot be explained by applying the known principles of human physiology, it is as yet impossible In this particular instance, even if we were to assume that the bees had some previous acquaintance with the distant place to which they were taken, we should still be quite unable to explain exactly how they got home. Locality-memory, however, would seem to imply some amount of intelligence. Readers desiring further details of the fascinating observations and experiments by Fabre on Mason-Bees and many other insects are referred to the original work, or the translation of the same which has recently appeared.

to say.

Suggestions have more than once been made in the course of this book as to the kind of investigation which amateur naturalists

might profitably attempt. The habits of Insects and other higher Invertebrates offer an inexhaustible and intensely-interesting field to multitudes of such workers. Accurate observations recorded with scrupulous exactness are here badly needed, and those who enlarge our knowledge in this direction are contributing to the advance of two branches of knowledge, zoology and the science of mind (psychology), not to mention sociology and education, both of which are intimately connected with the latter.

It is indispensable that observations on instinct and intelligence should be made with a perfectly open mind, and not with the object of collecting material for the support of this or that view. And it is peculiarly necessary to remember that the mental standard of human beings can only be applied with many reservations in explanation of the actions of animals, especially when dealing with creatures like Insects which, though of highly complex structure, have specialized on lines of their own. A series of observations made in this spirit, and which are not only of the utmost value but of absorbing interest, have been recorded by Dr. and Mrs. Peckham (On the Habits and Instincts of the Solitary Wasps). These insects have attracted much attention on account of their habit of storing up caterpillars, flies, spiders, &c., for the benefit of their progeny, the victims having previously been stung (see vol. iii, p. 391). Instincts of very complex nature are here involved, but the zoologists just mentioned have shown that these instincts are not so stereotyped as commonly supposed, there being a certain amount of adaptability to circumstances, which is strong presumptive proof of some degree of intelligence. Pure instinct is manifested by the fact that any particular species of these wasps is always found to select the same kind of prey, and, for a given species, there is so much uniformity in the mode of nest-construction, the way of disabling the victims, the manner of taking them into the nest, &c., that instinct is undoubtedly the dominant factor. But, except in regard to the kind of prey, there is a sufficient amount of adjustment to varying circumstances to warrant the conclusion that intelligence also plays some part in the complex series of operations. It appears, for example, that the prey is not uniformly stung in the nerve-cord, as once believed, and it may be killed instead of paralysed by its injuries, proving in either case suitable food for the larvæ. This certainly discounts the view that this part of the series of actions is stereotyped by instinct.

And a convincing proof of the power of profiting by experience which constitutes intelligence is given in a letter of Dr. Peckham's, quoted by Lloyd Morgan (in Animal Behaviour), in reference to a species (Sphex ichneumonea) which preys upon grasshoppers, and after leaving them a short time while she makes an excursion into the nest, returns and drags them in by their feelers. One individual, being several times thwarted in her storing work by removal of the victim to a short distance when she was in the nest, soon learnt the inadvisability of losing sight of her booty, and either at once dragged it into the hole or, straddling over it, substituted pushing for pulling.

One of the most remarkable points about the nesting-instinct in so many solitary insects is the elaborate provision made for the welfare of offspring which will never be seen, and which commonly require food of quite different nature from that taken by the adult. The parent would seem to be urged on by irresistible impulses, and can hardly be supposed to realize the meaning of its work, except perhaps in a very dim sort of way. Butterflies and Moths illustrate the food-question very clearly. It is true that they do not construct and store nests, like the solitary wasps just mentioned, but they instinctively lay their eggs on special sorts of plant, upon the leaves of which their voracious offspring are destined to feed. A Peacock Butterfly (Vanessa Io), for example, selects a nettle for the purpose, but her own food consists of nectar drawn from the recesses of flowers by means of suctorial mouth-parts, differing greatly from the powerful biting jaws of the leaf-eating caterpillar. It is almost impossible to believe that remembrance of her own larval days guides to the choice of a suitable place for egg-laying, for the caterpillar is converted into the adult by a series of revolutionary changes which amount to reconstruction.

INSTINCT AND INTELLIGENCE IN MOLLUSCS (MOLLUSCA).—Comparatively few observations have been made upon the members of this group, some of which are very highly organized. Several good illustrations of both instinct and intelligence have, however, been recorded.

The Octopus is one of the highest Molluscs, and appears to be a very intelligent creature. Schneider saw a young one seize a hermit-crab and then let it go, being stung by the zoophytes covering its shell. For some time at least this individual was observed to avoid hermit-crabs, having learnt to associate them