172 SUPPLEMENT TO 



back into the nest and used as food. By a fortunate 

 chance I have been able to prove that the seeds will 

 germinate in an undisturbed granary when the ants 

 are prevented from obtaining access to it ; and this 

 goes to show not only that the structure and nature 

 of the granary chamber is not sufficient of itself to 

 prevent germination, but also that the presence of the 

 ants is essential to secure the dormant condition of 

 the seeds. 



I discovered in two places portions of distinct nests 

 of AUa sfructor which had been isolated owing to the 

 destruction of the terrace- wall behind which they lay, 

 and there the granaries were filled up and literally 

 choked with growing seeds, though the earth in 

 which they lay completely enclosed and concealed 

 them, until by chance I laid them bare ! In one case 

 I knew that the destruction of the wall had only 

 taken place ten days before, so that the seeds had 

 sprouted in this interval. 



My experiments also tend to confirm this, and to 

 favour the belief that the non-germination of the 

 seeds is due to some direct influence voluntarily exer- 

 cised by the ants, and not merely to the conditions 

 found in the nest, or to acid vapours which in certain 

 cases are given off by the ants themselves. 



In order to put this latter point to the test of 

 experiment, I confined about a hundred harvesting 

 ants {A, structor), with their queen and several larvse, 

 in a glass test-tube eight inches long and one inch in 

 diameter, closed with a cork and filled up to within 

 about an inch of the cork with damp sandy soil, most 

 of which was taken from the ants' nest. 



I added six peas, six cress and six millet, and then 



