354 TUB POPULAR SCIENCE MONTHLY. 



genuity, has been made by Prof. Heer. He points out that, according 

 to the reckoning of the most discreet geologists, at least a thousand 

 centuries must have elapsed since Britain was severed from the Conti- 

 nent of Europe. For this long stretch of time, therefore, British 

 animals must have been cut otf from their representatives in France, 

 Belgium, and Switzerland. If, then, the habits of a certain slave- 

 holding ant {Formica sanguined) in England are found identical, as 

 he maintains, with the habits of the same species in Switzerland, there 

 is a strong presumption that its economy has undergone no change for 

 the last hundred thousand years. To this argument, we must reply 

 that the isolation between British and Continental species of insects is 

 by no means so complete as is here assumed. Winged ants travel 

 very considerable distances, and, if our memory does not deceive us, 

 have been met with out at sea. That a part of a swarm should he 

 blown over from the French coast to England, or vice versa, is by no 

 means improbable. And it is well known that if a party of working- 

 ants fall in with an impregnated female of their own species, they im- 

 mediately lead her to their nest and install her in a royal apartment. 

 That there may have been within the last ten thousand or even one 

 thousand years direct intercommunication of this kind between the 

 slave-making ants of England and those of Switzerland, seems to us 

 fully more probable than the contrary supposition. 



Again, we may ask whether the conditions under which ants would 

 be respectively placed in Switzerland and in England are not so 

 closely analogous that their social development must proceed on 

 parallel lines ? In both they would encounter nearly the same cli- 

 mate, the same food, and the same enemies. Surely, therefore, a close 

 correspondence in habits is no decisive proof of their immobility. 

 But, after all, is there such an absolute accord between the habits of 

 the Swiss and of the British ants as the validity of Prof. Heer's argu- 

 ment would require r Mr. Darwin thinks that in the nests of the 

 British Formica sanguinea there is a relatively smaller proportion of 

 slaves, which therefore play a less important part in the economy of 

 the ant-hill. Messrs. Kirby and Spence record a fact which, isolated 

 as it is, seems to us to overthrow altogether the hypothesis of abso- 

 lute stationariness. Ants have been found, namely, to establish their 

 nest in the interval between the double casing of a glass beehive. 

 Now, as such beehives are artificial objects, and of very recent origin, 

 they cannot have come in the way of the ants for any great length of 

 time. They offered, however, a certain advantage in the uniform 

 temperature and the shelter which they supplied. This fact must 

 have been recognized by some prying ant, and the discovery, being 

 communicated to its comrades, was turned to practical account. Is 

 not this case the exact parallel of a step in the development of human 

 civilization ? And if, as we see, ants can in one case observe a phe- 

 nomenon, reason on such observation, and work out their conclusions 



