90 BRITISH BIRDS. [vol. xiv. 



regarded merely as an extension of the male's territory, and 

 as already noted the female was never seen to cross from the 

 new to the old territory which the male visited but rarely, 

 and then only for food. 



In this connection I should like to direct the attention 

 of ornithologists to M. Hacbet-Souplet's results obtained 

 with rats in the laboratory {La Genese des Instincts, Paris, 

 1912, p. 258 et seq.) This observer placed a number of rats 

 in a large enclosure, each square metre of the ground being 

 provided with the same weight of food each day. He found 

 that each rat occupied and defended an area, the extent of 

 which was directly proportional to the muscular power of 

 the rat, as measured by a dynamometer. When the squares 

 were provided with unequal quantities of food, the strongest 

 rats did not always occupy the best locations. The first 

 occupation of a square seemed to be due entirely to chance. 

 If the food was sufficient the animal was content, and only 

 where the quantity of food fell below the necessary minimum, 

 did fights ensue for the possession of territories. Privation, 

 however, induced temporary association of the rats in the 

 endeavour to satisfy their needs. Hachet-Souplet inveighs 

 against the assumption that reason, ideas of justice, and 

 the right to live intervene in the behaviour underlying the 

 Law of Territory, and his opinion seems to be fully borne out 

 by the results of his experiments. 



