208 SPOLIA ZEYLANICA. 



There is a farther point worthy of note in the cultivation 

 under the bell-jar. After a short time, 1-2 days, one sees the 

 Termites in large numbers lying upon their backs and realizes 

 that they are suffocated. Termites taken from the same culture 

 and kept between two hermetically closing watch-glasses without 

 pieces of cake, which were kept during the same time, lived and 

 were perfectly active. It follows from this that the suffocation 

 of the former was not due to lack of air, especially since access 

 of air to the main culture was not entirely prevented. 



Upon raising the bell-jar it was noticeable that the space was 

 filled with a gas mixture which was clearly very different in its 

 composition from the atmospheric air. In breathing it one 

 experienced a strong oppression, as well as a very remarkable 

 odour like that of the gas proceeding from fermenting substances. 

 In any case a large amount of carbonic acid gas had formed, if 

 not other gases, perhaps as a collateral result of the growth of 

 the fungus at the expense of the wood. 



All those appearances which are observed under the special 

 conditions of culture outside the Termite nest are naturally 

 absent inside the hillock. There, through the special construction 

 of the nest, it is arranged that necessary temperature and 

 moisture for the development of the fungus remains constant. 

 The building material is up to a certain point waterproof, so that 

 neither an excessive evaporation from the fungus cake through the 

 wall of the chamber, nor the entrance of rain from without, ensues. 



What however is most important is that the entire method of 

 construction of the hillock ensures the elaborate ventilation of 

 its inner spaces ; the Termite hillocks with their chimney flues 

 are hygienic dwellings. 



The chimneys are air shafts which conduct away moisture, 

 carbonic acid gas, and other injurious gases, while fresh air can 

 enter through the lower openings. These ventilation flues can 

 at any time according to the increase of the stock, climatic varia- 

 tions, &c., be altered and adapted. Thus is explained the quite 

 different number of chimneys which arise from a Termite hillock, 

 and it would be of interest to undertake a comparative study of 

 the size and number of chimneys, size of hillock, number of 

 fungus chambers, climate and locality, building material, popula- 

 tion, and systematic position of the Termite species under question. 



That the draught in these chimneys can, under circumstances, 

 be considerable, is indicated by the application which travellers 

 have frequently found for the Termite nests. Quite recently it has 

 been repeatedly reported that our troops in South-West Africa 

 have used the Termite nests as ovens, selecting those forms 



