332 FERMENTATION ASCRIBED TO THE 



acid, ammonia, and water. In order to comprehend the chemical 

 process by which this conversion is effected, it is of much interest 

 to become acquainted with the intermediate compounds formed 

 by the elements. But in regard to the process itself, it is, che- 

 mically speaking, quite indifferent whether the first, second, or 

 third product, before they assume the final state, be in the form 

 of fungi, or of living animals (infusoria). These plants and ani- 

 mals are not the causes of the conversion, for they suffer after 

 death the same changes which finally occasion their complete 

 disappearance. 



The enormous layers of microscopic animals in the chalk (the 

 siliceous infusoria) do not contain any organic matter. The lime 

 of their shells, and the silica of their bony coverings, were ob- 

 tained from the water in which they were developed, if this 

 water had been deficient in lime, or in silica, these animals could 

 not have been produced ; and if they had not found nourishment 

 in the products of the putrefaction of former species (the remains 

 of which are found in the musc/ie/kalk), they would not have been 

 developed ; and without the co-operation of both these causes, 

 they could not have formed such extensive masses and layers as 

 they actually do. 



But these animals are not the causes of the formation of the 

 chalk, or of the layers of flint, and as little are they the cause of 

 the decay and putrefaction of those substances, which yielded to 

 them their organic constituents. Without these animals there 

 might not have been chalk, but there would have been marble, or 

 another limestone ; and the silica would have been deposited as 

 siliceous schist, or as quartz, after the evaporation of the water. 

 Hence it is only the form which is given to the layers by organic 

 life ; but the substance of these strata (chalk) is chemically in no 

 respect different from crystallized calcareous spar: in fact, the 

 same explanation of their origin might be made as that adopted in 

 the case of the older limestone formations. 



The conversion of the constituents of an elephant into aerial 

 compounds is the same process, and is effected by the same causes 

 as those occasioning the destruction of the carcase of the micro- 

 scopical animals, which themselves obtained their elements from 



