164 THE ANIMAL 



and it would seem certain that those species which have 

 gathered into their structure siliceous particles, have, on 

 the death of the animals, formed centres to which further 

 crystals of flint have attached themselves ; and that this has 

 been the origin of the stone now known as Flint. The 

 following passage, by Professor Rymer Jones, is given in 

 support of this theory : " Were we to inform our young 

 readers that flints have been sponges, and that every flint 

 wherewith in many parts of the country the roads are 

 paved, and which, before the invention of lucifer matches, 

 constituted almost the only means of obtaining fire, had 

 grown at the bottom of the sea, rooted upon the rocks, 

 and sucking in the surrounding water through innume- 

 rable pores upon their surface, which conveyed through 

 every part of their soft texture materials for their subsis- 

 tence, we could scarcely expect the assertion to be 

 credited at least, without considerable hesitation ; and yet 

 no fact in natural history is more easily demonstrated. 

 Not only do the fragments of flints examined under the 

 microscope reveal the fossilised texture of the sponge, but 

 not unfrequently the shells of the animalcules upon which 

 they lived are found in their substance ; and even portions 

 of the sponge itself, as yet unpetrified, are often contained 

 in their interior." 



Various species of sponge are used : two from the 

 Levant, and another, of a very coarse kind, from Florida 

 and the West Indies. The trade is carried on chiefly by 

 the Turks and the inhabitants of the Bahama Islands. 

 The boats used in the gathering of sponge on the coasts 

 of Barbary, Candia, and Syria, furnish employment for 

 about 5,000 men, the sponge being obtained either by 

 diving or dredging. The value of the sponges collected 

 in Greece and Turkey is from ,90,000 to ; 100,000 

 annually. We import about 200,000 or 300,000 Ibs. of 

 Mediterranean sponge, at from seven to sixteen shillings. 



