46 



NA TURE 



\_Nov. 12, 1885 



which had been removed two or three times from her, and her 

 anxiety was excessive, as she tried to find out if they were all 

 present, or if any were still missing. She kept puzzling and 

 running her eyes over them backwards and forwards, but could 

 not satisfy herself. .She evidently had a vague notion of count- 

 ing, but the figure was too large for her brain. Taking the two 

 as they stood, dog and Damara, the comparison reflected no 

 great honour on the man." But even if "Dinah" had been 

 clear on this subject, it might be said that she knew each puppy 

 personally, as collies are said to know sheep. The same remark 

 applies generally to animals and their young. Swans, for in- 

 stance, are said to know directly if one of their cygnets is missinsj, 

 but it is probable that they know each young bird individually. 

 This explanation applies with less force to the case of eggs. 

 According to my bird-nesting recollections, which I have re- 

 freshed by more recent experience, if a nest contains four eggs, 

 one may safely be taken ; but if two are removed, the bird 

 generally deserts. Here, then, it would seem as if we had some 

 re.ason for supposing that there is sufficient intelligence to dis- 

 tinguish three from four. An interesting consideration arises 

 with reference to the number of the victims allotted to each cell 

 by the solitary wasps. One species of Ammophila considers one 

 large caterpillarofiVi'fj'Mrt sege/um enough ; one species of Eumenes 

 supplies its young with 5 victims ; another 10, 15, and even up to 24. 

 '1 he number appears to be constant in each species. How does 

 the insect know when her task is fulfilled ? Not by the cell being 

 filled, for if some be removed she does not replace them. When 

 she has brought her complement she considers her task accom- 

 plished, whether the victims are still there or not. How, then, 

 does she know when she has made up the number 24? Perhaps 

 it will be said that each species feels some mysterious and innate 

 tendency to provide a certain number of victims. This would, 

 under no circumstances, be any explanation ; but it is not in 

 accordance with the facts. In the genus Eumenes the males 

 are much smaller than the females. Now, in the hive-bees, 

 humble-bees, wasps, and other insects, where such a difference 

 occurs, but where the young are directly fed, it is of course 

 obvious that tlie quantity can be proportioned to the appetite of 

 the grub. But in insects with the habits of Eumenes and Am- 

 mophila the case is different, because the food is stored up once 

 for all. Now, it is evident that if a female grub was supplied 

 with only food enough for a male she would starve to death : 

 while if a male grub were given enough for a female it would 

 have too much. No such waste, however, occurs. In some 

 mysterious manner the mother knows whether the egg will pro- 

 duce a male or female grub, and apportions the quantity of food 

 accordingly. She does not change the species or size of her 

 prey ; but if the egg is male she supplies 5 ; if female, lo 

 victims. Does she count ? Certainly this seems very like a 

 commencement of arithmetic. At the same time it would be 

 very desirable to have additional evidence how far the number is 

 really constant. Considering how much has been written on 

 instinct, it seems surprising that so little attention has been 

 directed to this part of the subject. One would fancy that there 

 ought to be no great difficulty in determining how far an animal 

 could count ; and, whether, for instance, it could realise some 

 very simple sum, such as that two and two make four. But 

 when we come to consider how this is to be done the problem 

 ceases to appear so simple. We tried our dogs by putting a 

 a piece of bread before them and preventing them from touching 

 it until we had counted seven. To prevent ourselves from un- 

 aitentionally giving any indication we used a metronome (the 

 .nstrument used for giving time when practising the pianoforte), 

 and to make the beats more evident we attached a slender rod 

 to the pendulum. It certainly seemed as if our dogs knew when 

 ihe moment of permission had arrived ; but their movement of 

 taking the bread was scarcely so definite as to place the matter 

 beyond a doubt. Moreover, dogs are so very quick in seizing 

 .any indication given them, even unintentionally, that, on the 

 whole, the attempt was not satisfactory to my mind. I was the 

 more discouraged from continuing the experiment in this manner 

 by an account IVIr. Huggins gave me of a veiy intelligent dog 

 belonging to him. A number of cards were placed on the 

 ground, numbered respectively I, 2, 3, and so on up to 10. A 

 question is then asked : the square root of 9 or 16, or such a 

 sum as 6 X 52 - 3. Mr. Huggins pointed consecutively to the caivjs, 

 and the dog barked when lie came to the right one. Now Mr. 

 Huggins did not consciously give the dog any sign, yet so quick 

 was the dog in seizing the slightest indication, that he was able 

 to give the correct answer. This observation seems to me of 



great interest in connection with the so-called "thought-reading." 

 No one, I suppose, will imagine that there was in this case any 

 " thought-reading " in the sense in which this word is used by 

 Mr. Bishop and others. Evidently "Kepler" seized upon 

 the slight indications unintentionally given by Mr. Huggins. 

 The observation, however, shows the great difficulty of the sub- 

 ject. I have ventured to bring this question before the Section 

 partly because I shall be so much obliged if any lady or gentle- 

 man present will favour me with any suggestions ; and partly in 

 hope of inducing others with more leisure and opportunity to 

 carry on similar observations, which I cannot but think must 

 lead to interesting results. 



Dr. Flower remarked that the crowded state of the room was 

 sufficient evidence of the interest taken in whatever of the 

 numerous subjects Sir John Lubbock cared to enlighten them 

 upon. Sir John Lubbock was unable to make his dog count seven , 

 but .a dog at a place where he (Dr. Flower) was living recently 

 certainly knew when the seventh day of the week came. The 

 dog, most eager on every otherday of the week to go for a walk, 

 betrayed no desire to go on Sunday when his master took up hi< 

 hat and stick to go to church. It struck him that the method 

 which Sir John had adopted was the only one by which they 

 could put themselves in relation to the minds of these animals — 

 namely, the method of kindness and encouragement. Too 

 many had tried to do these things by a system of intimidation 

 and cruelty, but he did not think they could really know what 

 dogs could do, and bring out their faculties, without ipatience 

 and perseverance, encouragement, and uniform kindness. 



Miss Catherine Rae explained the way in which she got a dog, 

 within three weeks, to ring a bell. She began by letting "Tiny ' 

 smell the bone of a mutton chop, and then tied the bone to the 

 string of the bell. At first "Tiny" was in a great tremor, but, 

 by taking her very kindly and stroking her, she found that she 

 could induce her to pull at the bone and so to ring the bell. 

 .•\fter that she tied a small piece of wood to the string, but the 

 dog would not pull it. At last she pulled her gently back till 

 the bell rang, and in this way, in the short course of three weeks, 

 with not more than one or two lessons a day, the dog would gi 

 and ring the bell by being told — " ' Tiny,' go and ring the bell. ' 

 At the end of three weeks she gave an evening party, and during 

 the evening they were all electrified by the sudden and violent 

 ringing of the belh "Tiny " had been neglected to be indulged 

 with any tit-bit, and had taken this means of receiving atten- 

 tion. 



Miss Becker said, with regard to the experiments with the 

 crow mentioned by Sir John, to show that it could not count 

 beyond three, that something of the same kind might happen 

 with a person. Place three eggs upon the table, and any one 

 could say there were three ; but if there were twelve he would 

 rec|uire to count them to be sure of the number. 



Mr. C. C. Walker gave an instance of a dog being taught 

 politics. He belonged to a family where Liberal politics pre- 

 vailed, and the dog showed his sympathy by growling fearfully 

 when the name of "Dizzy " was mentioned, and at the name of 

 his master giving expression to unbounded delight. Similar 

 demonstrations at public meetings, he added, were often made 

 with as little intelligence as those of the dog. 



Some other remarks were made, one gentleman suggesting 

 that as long as the dog was ignorant of the words " one," "two,' 

 "three," "four," he would not be able to counter get beyond tht 

 mere perception of magnitude. 



Sir John Lubbock thought with reference to the question ol 

 Sunday that there were so many slight indications in the house- 

 hold generally to distinguish the day that he had never been 

 able to regard that as proof of a dog counting, although it wa- 

 a very interesting fact in itself. As regards several of the other 

 cases they were clever tricks, but his suggestion was to operate 

 in exactly the opposite direction ; not to teach the dog, but tu 

 enable the dog to communicate with us. 



NITROGEN JN THE SOIL 



"pACH of the elements required for building up the frame of 

 ■'-' animals and plants is of equal importance from a scientific 

 standpoint, but in agriculture the various salts and substances 

 which yield food for crops or for cattle must necessarily be valued 

 according to their cost. There are exceptions to this rule, no 

 doubt. Gypsum is a cheap manure, but it has sometimes doubled 

 the clover crop, and kainit salts are comparatively cheap. Yet 



