February i, 1906] 



NA TURE 



315 



many of us will not agree that " a day will come when 

 the ether will be rejected as useless." 



The reader will place the book — if possible the 

 original, but faute de mieux its translation — on his 

 shelves with the intention of frequently spending an 

 instructive quarter of an hour with it. Each time he 

 carries out his intention he will realise more the truth 

 of the author's remark : " To doubt everything or to 

 believe everything are equally convenient solutions : 

 both absolve us from the necessity of thinking." 



Arthur Schuster. 



THE INTELLIGENCE OF ANIMALS. 



Comparative Studies in the Psycliology of Ants and 



of Higher Animals. By E. Wassmann, S.J. Pp. 



x + 200. (St. Louis, Mo., and Freiburg: B. Herder; 



London : Sands and Co., 1905.) Price 4s. 6d. net. 



\MONG those who have most carefully and 

 successfully studied the habits and psychology 

 of ants. Father Wassmann occupies a place in the 

 front rank. He has especially devoted his attention 

 in the curious and complicated relations which exist 

 between ants and their domestic animals. Of these, 

 In gives a list comprising no less than 1246 species! 

 Father Wassmann is an accurate and careful observer, 

 and his writings are most interesting. 



To show how conscientiously he has studied the 

 ants of his own district I may mention that he made 

 a census of the ants' nests round his home. Many 

 communities have more than one nest. Of Formica 

 sanguinea, which he regards as the most gifted of 

 European ants, he records 2000 nests belonging to 

 410 communities! Most of them have separate 

 summer and winter nests, or rather nests for warm 

 and drv, or cold and wet seasons. 



Father Wassmann is by no means one of those who 

 regard ants as exquisite automatons, " devoid even of 

 the simplest sensitive perception and cognition." I 

 quite concur with him — indeed, I expressed the same 

 opinion nearlv fiftv years ago — that " the life of ants 

 is the climax of development in instinctive life 

 throughout the animal kingdom"; and that "the 

 chasm between the psychic life of animals and that 

 of man, is, in many respects, wider between ape and 

 man, than between ant and man." 



Father Wassmann is also, I believe, quite correct 

 in alleging that Buechner and Brehm, and even 

 Romanes, have accepted many statements implying 

 intelligence on the part of animals for which there 

 was no sufficient evidence, some of which, indeed, were 

 quite absurd; and, secondly, that they have in some 

 cases built upon them conclusions for which there is 

 no foundation, and which will not stand the test of 

 critical examination. 



On the other hand, I am unable to follow him 

 when he altogether denies to ants anv, even the most 

 exiguous, rudiments of intelligence. As in the cases 

 of Darwin and Forel, the conclusion forced upon me 

 has been that animals, and especially ants, do possess 

 some elements of intelligence. In that we agree with 

 the vast majority of those who have studied dogs, 

 elephants, &c. 



NO. 1892, VOL. J2>~\ 



Father Wassmann defines intelligence as " the 

 power of acting with deliberation and self-conscious- 

 ness, of inventing new means for attaining various 

 purposes and thus making progress in civilisation." 

 But if ants are descended from an original common 

 stock in bygone times, no one will deny that they 

 have " invented new means for attaining various 

 purposes and thus making progress in civilisation." 

 Moreover, even now we see them adapting themselves 

 to the circumstances of their complex life in a manner 

 which it is surely an abuse of terms to call " instinc- 

 tive." He admits that the observations of all who 

 have studied ants conclusively demonstrate that ants 

 are not mere reflex machines, but beings endowed 

 with sensitive cognition and appetite, and with the 

 power of employing in the most various manner their 

 innate, instinctive faculties and abilities under the 

 influence of different sense-perceptions. Surely, then, 

 under his definition it is impossible to deny that they 

 have some intelligence. 



For instance, in constructing their nests, as Father 

 Wassmann admits, ants do not " cooperate with the 

 regularity of a machine or according to a rigid pat- 

 tern, but each ant with evident liberty follows her own 

 impulse and her own plan. ..." 



"As a rule the most zealous and skilful worker 

 is imitated most ; her zeal is catching, so that she 

 directs the activity of the others into the same 

 channel. " 



Indeed, Father Wassmann 's fairness and love of 

 truth compel him to make several candid admissions 

 which seem fatal to his position. For instance, an 

 Algerian ant (Myrmecocystus altisquamis) has wide 

 open entrances to the nest. A colony, however, which 

 Forel brought to Switzerland, being much annoved 

 by the attacks of Tetramorium caespitum, gradually 

 contracted the doorways. On this Father Wassmann 

 admits that, " as Forel says, these facts afford irre- 

 futable evidence of the great plasticity of ant instinct. 

 For, this instinct is not merely a nervous mechanism 

 forced to operate along uniform lines ; it includes 

 sensitive cognition and appetite, which are not only 

 of an organic but also of a psychic nature." 



Again, " within these limits, however, we find a 

 wonderful adaptation of means to the end, and at 

 times a marvellous sagacity of animal instinct, which 

 appears nowhere else to such advantage." 



" This phenomenon manifests the marvellous 

 sagacity and quasi-intelligent plasticity of animal in- 

 stinct, which can hardly be styled 'automatism.' 

 Neither can it be identified with intelligence properly 

 so-called, for this would suppose rational knowledge 

 of the internal laws governing the growth of the 

 ant organism, a knowledge far surpassing even the 

 intelligence of man and entirely beyond the reflections 

 and experience of ants." 



Surely, however, if ants have sagacity they must 

 have intelligence. Nor is the attribution to them of 

 " sagacity " an isolated case. Again on p. 157 he 

 says : — 



" Their sagacity is instinctive, essentially different 

 from intelligence and reflection. Ants are in their 

 every action guided directly by sensitive perceptions, 

 not by intellectual ideas. The enigma, therefore, is 



