Oct. 7, 1 875 J 



NATURE 



507 



ling in the same meteorite, oflfered a difficult problem which I 

 had taken in hand. One little crystal, however, carrying a por- 

 tion of a zone with four consecutive faces, picked out in 1867, 

 furnished the final key to its crystallography. 



N. S. Maskelyne 

 (TV be continued.') 



INSTINCT AND ACQUISITION.* 

 CJ O great was the influence of that school of psychology which 

 '^ maintained that we and all other animals had to acquire in 

 the course of our individual lives all the knowledge and skill 

 necessary for our preservation, that many of the very greatest 

 authorities in science refused to believe in those instructive per- 

 formances of young animals about which the less learned multi- 

 tude have never had any doubt. For example, Helmhaltz, than 

 whom there is not, perhaps, any higher scientific authority, says : 

 "The young chicken very soon pecks at grains of corn, but it 

 pecked while it was still in the shell, and when it hears the hen 

 peck, it pecks again, at first seemingly at random. Then, when 

 it has by chance hit upon a grain, it may, no doubt, learn to 

 notice the field of vision which is at the moment presented to it." 



At the meeting of this Association in 1872, I gave a pretty full 

 account of the behaviour of the chicken after its escape from the 

 shell. The facts observed were conclusive against the individual- 

 experience psychology. And they have, as far as I am aware, 

 been received by scientific men without question. I would now 

 add tliat not only does the chick not require to learn to peck at, 

 to seize, and to swallow small specks of food, but that it is not a 

 fact, as asserted, and generally supposed, that it pecks while still 

 in the shelL The actual mode of self-delivery is just the reverse 

 of pecking. Instead of striking forward and downward (a move- 

 ment impossible on the part of a bird packed in a shell with its 

 head under its wing), it breaks its way out by vigorously jerking 

 its head upward, while it turns round within the shell, which is 

 cut in two — chipped right round in a perfect circle some distance 

 from the great end. 



Though the instincts of animals appear and disappear in such 

 seasonable correspondence with their own wants and the wants 

 of their offspring as to be a standing subject of wonder, they have 

 by no means the fixed and unalterable character by which some 

 would distinguish them from the higher faculties of the human 

 race. They vary in the individuals as does their physical struc- 

 ture. Animals can learn what they did not know by instinct and 

 forget the instinctive knowledge which they never learned, while 

 their instincts will often accommodate themselves to considerable 

 changes in the order of external events. Everybody knows it to 

 be a common practice to hatch ducks' eggs under the common 

 hen, though in such cases the hen has to sit a week longer than on 

 her own eggs. I tried an experiment to ascertain how far the time 

 of sitting could be interfered with in the opposite direction. Two 

 hens became broody on the same day, and I set them on dummies. 

 On the third day I put two chicks a day old to one of the hens. 

 She pecked at them once or twice ; seemed rather fidgety, then 

 took to them, called them to her and entered on all the cares of 

 a mother. The other hen was similarly tried, but with a very 

 different result. She pecked at the chickens viciously, and both 

 that day and the next stubbornly refused to have anything to do 

 with them. 



The pig is an animal that has its wits about it quite as soon 

 after birth as the chicken. I therefore selected it as a subject of 

 observation. The following are some of my observations : — 

 That vigorous young pigs get up and search for the teat at once, 

 or within one minute after their entrance into the world. That 

 if removed several feet from their mother, when aged only a few 

 minutes, they soon find their way back to her, guided apparently 

 by the grunting she makes in answer to their squeaking. In the 

 case I observed the old sow rose in less than an hour and a half 

 after pigging, and went out to eat ; the pigs ran about, tried to 

 eat various matters, followed their another out, and sucked while 

 she stood eating. One pig I put in a bag the moment it was 

 bom and kept it in the dark until it was seven hours old, 

 when I placed it outside the sty, a distance of ten feet from 

 where the sow lay concealed inside the house. The pig soon re- 

 cognised the low grunting of its mother, went along outside the 

 sty struggling to get under or over the lower bar. At the end 

 of five minutes it succeeded in forcing itself through under the 

 bar at one of the lew places where that was possible. No sooner 

 in than it went without a pause into the pig-house to its mother, 

 * Read at the Bristol meeting of the British Association. 



and was at once like the others in its behaviour. Two little pigs 

 I blindfolded at their birth. One of them I placed with its 

 mother at once : it soon found the teat and began to suck. Six 

 hours later I placed the other a little distance from the sow ; it 

 reached her in half a minute, after going about rather vaguely ; 

 in half a minute more it found the teat. Next day I found that 

 one of the two left with the mother, blindfolded, had got the 

 blinders off ; the other was quite blind, walked about freely, 

 knocking against things. In the afternoon I uncovered its eyes, 

 and it went round and round as if it had had sight, and had 

 suddenly lost it. In ten minutes it was scarcely distinguishable 

 from one that had had sight all along. When placed on a chair 

 it knew the height to require considering, went down on its 

 knees and leapt down. When its eyes had been unveiled twenty 

 minutes I placed it and another twenty feet from the sty. The 

 two reached the mother in five minutes and at the same moment. 



Different kinds of creatures, then, bring with them a good deal 

 of cleverness, and a very useful acquaintance with the established 

 order of nature. At the same time all of them later in their 

 lives do a great many things of which they are quite incapable 

 at birth. That these are all matters of pure acquisition appears 

 to me an unwarranted assumption. The human infant cjinnot 

 masticate ; it can move its limbs, but cannot walk, or direct its 

 hands so as to grasp an object held up before it. The kitten 

 just born cannot catch mice. The newly hatched swallow or 

 tomtit can neither walk, nor fly, nor feed itself. They are as 

 helpless as the human infant. Is it as the result of painful 

 learning that the child subsequently seizes an apple and eats it ? 

 that the cat lies in wait for the mouse ? that the bird finds its 

 proper food and wings its way through the air ? We think not. 

 With the development of the physical parts, comes, according to 

 our view, the power to use them, in the ways that have preserved 

 the race through past ages. This is in harmony with all we 

 know. Not so the contrary view. So old is the feud between 

 the cat and the dog, that the kitten knows its enemy even before 

 it is able to see him, and when its fear can in no way serve it. 

 One day last month, after fondling my do^, I put my hand into a 

 basket containing four blind kittens, three days old. The smell 

 my hand had carried with it set them puffing and spitting in a 

 most comical fashion. 



That the later developments to which I have referred are not 

 acquisitions can be in some instances demonstrated. Birds do 

 not learn to fly. Two years ago I shut up five unfledged swallows 

 in a small box not much larger than the nest from which they 

 were taken. The little box, which had a wire front, was hung 

 on the wall near the nest, and the young swallows were fed by 

 their parents through the wires. In this confinement, where they 

 could not even extend their wings, they were kept until after 

 they were fuUy fledged. Lord and Lady Amberley liberated the 

 birds and communicated their observations to me, I being in 

 another part of the country at the time. On going to set the 

 prisoners free, one was found dead — they were all alive on the 

 previous day. The remaining four were allowed to escape one 

 at a time. Two of these were perceptibly wavering and un- 

 steady in their flight. One of them, after a flight of about ninety 

 yards, disappeared among some trees ; the other, which flew 

 more steadily, made a sweeping circuit in the air, after the 

 manner of its kind, and alighted, or attempted to alight, on a 

 branchless stump of a beech ; at least it was no more seen. No. 

 3 (which was seen on the wing for about half a minute) flew 

 near the ground, first round Wellingtonia, over to the other side 

 of the kitchen-garden, past the bee-house, back to the lawn, 

 round again, and into a beech-tree. No. 4 flew well near the 

 ground, over a hedge twelve feet high to the kitchen-garden 

 through an opening into the beeches, and was last seen close to 

 the ground. The swallows never flew against anything, nor 

 was there, in their avoiding objects, any appreciable difference 

 between them and the old birds. No. 3 swept round;the Wel- 

 lingtonia, and No. 4 rose over the hedge just as we see the old 

 swallows doing every hour of the day. I have this summer 

 verified these observations. Of two swallows I had similarly 

 confined, one, on being set free, flew a vard or two too close to 

 the ground, rose in the direction of a beech-tree, which it grace- 

 fully avoided ; it was seen for a considerable time sweeping 

 round the beeches and performing magnificent evolutions in the 

 air high above them. The other, which was observed to beat 

 the air with its wings more than usual, was soon lost to siyht be- 

 hind some trees. Titmice, tomtits, and wrens I have made the 

 subjects of a similar experiment and with similar results. 



Again, every boy who has^rought up nestlings with the hand 



