Chapter 9

Instinct.

How the various instincts of animals, the homing instinct of birds and insects, the building instincts, the migrating instinct, etc., could have been developed though forces working by natural selection or any other law, is a question which has called forth much discussion. It cannot be said that the explanations contained in the pages of Darwin, Romanes, and Spencer are satisfying. The difficulty that remains unsolved is similar to that (already considered) of rudimentary structures. On instinct depends the existence of most animals. According to the theory these instincts have been developed by slow degrees. Hence there must have been a time when these instincts, because not yet completely developed, were useless to the animal. But if useless, the animal must have perished. The strength of this objection to the evolutionary hypothesis will become clear from a brief study of the manner in which animal life is bound up with the proper functioning of instinct.

Consider, for instance, the dependence of the honey bee and her hive on the functions, every one instinctive, of queen, workers, and drones. There is the queen, whose sole work is to lay eggs; the drones, or males, whose function it is to fertilize the queen; and the workers, which are females undeveloped sexually. In these three kinds of individuals we see a combination of many most remarkable instincts and peculiarities of structure which look to the good of the community. How could they have been produced by evolution? The workers are sterile and leave no offspring, consequently their instincts cannot be inherited from bees of their own class. Each generation of workers is isolated from all succeeding generations. A colony of bees is not like a community of civilized human beings in whom many of the wants are artificial, and which may remain unsupplied, with simply a certain amount of discomfort, but the wants which the instincts of bees supply are imperative, and, therefore, the instincts themselves, as a whole, are necessary to the existence of the bees. Their instincts are all linked together as a necessary chain, so that if one should fail the community would perish. Each kind of work is perfectly done, and yet the workers are totally unconscious as to what will be the result of their labors. For the most part they work for future generations of their colony, and not for themselves, and yet they are as careful and diligent as if they were guided by the highest intelligence and the most selfish motives [tr. note: sic no punctuation]. Fairhurst, whom we are quoting, adds: "There is nothing more wonderful and mysterious in nature than the instincts of bees. What can be more remarkable than that instinct of the workers which causes them to prevent the queen from stinging to death the young queens in their cells? Here we see the instinct of the workers opposing that of the queen, and thus saving the colony and insuring the propagation of the species. And yet at other but proper times the workers permit the old queen to kill the young ones in their cells. How could these instincts in the workers, which act in exactly opposite ways by just the right times for the welfare of the community, have ever been evolved? Or how could that instinct have arisen which causes two queens when engaged in combat to refrain from inflicting the mortal sting if they would mutually destroy each other, and thus leave the hive without a queen?--acting as if they knew that the life of one of them was necessary for the welfare of the community."

Concerning the modifications of structure and the instincts necessary to produce the web of the spider, Fairhurst quotes the following from Orton's _"Zoology."_ "Spiders are provided at the posterior end with two or three pairs of appendages called spinnerets, which are homologous (correspond structually) [tr. note: sic] with legs. The office of the spinnerets is to reel out the silk from the silk-glands, the tip being perforated by a myriad of little tubes through which the silk escapes in excessively fine threads. An ordinary thread, just visible to the naked eye, is the union of a thousand or more of these delicate streams of silk. These primary threads are drawn out and united by the hind legs." From this we see that two special glands, capable of secreting a soft material that can be readily drawn into the finest threads of the greatest strength, requiring no perceptible time for drying, and two to four spinnerets perforated by more than a thousand of the smallest apertures, and hind legs modified so that they can be used to draw out the web through the spinnerets, and also the instincts which enable the spider to use its web to advantage, must all have been evolved. To evolve the silk glands would have required, as for most other organs, a long period of incipiency, during which they would have been useless. We can not assume that a substance so exceptional in its character as the web of the spider could have been suddenly produced by evolution. But the glands would be useless without spinnerets. The hypothesis asks us to assume that two or three pairs of legs that were probably at one time useful for locomotion became so modified that they could perform the function of spinnerets. But in what conceivable way could locomotive legs have become so modified and pierced with more than a thousand apertures through which the web is drawn? And how could these organs serve their purpose while the complex instincts required for their functioning were only in course of development?

From a German monthly devoted to aquaria, we quote the following: "But now, dear readers, we come to a fish which shows an exceptionally peculiar and touching care for its young--the mouth-brooder, _Haplochromis Strigigena_ (formerly _Paratilapia Multicolor_). This fish is so much concerned about the safety of its young, that it knows no better and no more secure place than its own mouth in which to preserve them. In no other division of the animal kingdom can we find such an interesting example of fostering care for the young as we find in this species of fish. Immediately after emitting the spawn the female again gathers up the eggs and packs them away in her mouth like herring in a barrel. She naturally must employ the organs of the throat and also the organs between the gills and thus the appearance of the animal is greatly changed even to the extent that it looks very much like as if she had a craw. Furthermore, during ths [tr. note: sic] entire period, which is about fourteen days, the little animal cannot take food and is hampered very much in her movements. Therefore in case of imminent danger it becomes necessary for her to cast out the entire brood which then wretchedly perish, and for this reason it is to be recommended to disturb or disquiet these animals during this period as little as possible. Even after the young leave the mother of their own accord, they always flee to her protecting mouth, and thus they present an exciting aspect, when they are first seen peacefully and contentedly playing about the mother fish, until a shadow or a sudden thrust warns them of danger and quick as lightning they dart into her mouth.

"If the fostering care of this mouth-brooding fish is regarded as wonderful and singular, what should one then say, if another fish is spoken of which does not regard this kind of protection as sufficient, and which therefore causes its eggs to hatch outside the surface of the water. The exceedingly adorned and elegant _Phyrrhylima Filamentosa_ performs this masterpiece of truest love. With great dexerity [tr. note: sic] this fish darts from 5 to 7 cm. above the surface of the water and there fastens its eggs on the walls of the aquarium--usually in one corner. Even though one must and can preserve damp air by covering the aquarium, the spawn would nevertheless surely dry up, if the fish itself were not constantly concerned to keep the spawn damp by an extended bombardment of little drops of water. In the performance of this act the fish remains near the surface of the water and then by a quick upward movement of the fins of the tail it throws a drop of water upon the spawn in such an expert manner as is truly admirable. One must also keep in mind here that the spawn require from three to five days for hatching, and now one can understand what a huge task this little fish performs and what efforts are required. Later on the young hatch and then slide down the slick wall of the aquarium into their native element." (V. Schloemp in _"Blaetter fuer Aquarien und Terrarienkunde,"_ Stuttgart, Sept. 1913.)

In all the domain of natural science there are no wonders more amazing than those of instinct. The subject is simply inexhaustible. Moreover, every animal is absolutely dependent on instinctively performed actions and habits. The life-story of many wasps, of the various ants,--someone has called the brain of the ant the most wonderful speck of protoplasm in the world,--and of the insects generally, is bound up with instincts that partly interlock marvellously with the life-story of plants, and which are, even viewed in themselves, the greatest wonders of creation. The questions insistently call for an answer: How could these instincts preserve the animal when they were still in an incipient, undeveloped state? How could they arise through natural selection (which is simply _accident,_ of course), at all? Darwin says that there are instincts "almost identically the same in animals so remote in the scale of Nature, that we cannot account for their similarity by inheritance from a common progenitor, and consequently must believe that they were independently acquired through natural selection." Again he says "Many instincts are so wonderful that their development will probably appear to the reader a difficulty sufficient to overcome my whole theory."

And here, in the vernacular of the day, we would depose that Mr. Darwin _"said something."_