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It is well known that animals as well as vegetables pre- 

 pare, by various occult procefTes, fluids powerfully corrofive : 

 the viper fecretes a deadly poifon, which is forced through 

 the cavity of its fang ; the pifmire, and fome other infefls, 

 eje6l a powerful acid, capable of didblving calcareous ftone. 

 Surely then it may mofl reafonably be admitted that, by 

 fome filch chemical mehns prepared in the great elabora- 

 tory of nature, thefe tefta'ceous Afcidia perform tlie part 

 alTigned to them by the Creator of the tmiverfe. 



All the teflaceous animals hitherto difcoVered in the 

 Bi'itiJIj feas to be perforators, have, upon examination, 

 proved to be Afcidia, with the two tubes terminal, and more 

 Or lefs connected, through which alone they take their food ; 

 but it is probable the larger tube is the principal inftrument 

 for taking in the fluid element, and widi it the innumerable 

 animakuli with \Vhich fea water abounds ; and the fmaller 

 may ufually reje(5l it after it has been lirained through the 

 vifcera of the aniinal, as Mr. Home obferves with refpect to 

 the Teredo. We have, however, noticed that the water 

 is taken in, and difcharged at both tubes occafionally, by 

 fome teflaceous Afcidia. 



In all thefe animals, their tubes or fyphons only have a 

 communication with the water through a fmall opening to 

 tlieir chamber ; and the chamber is enlarged as the growth 

 of the animal requires, and not for the purpofe of food ; for 

 although a jwrtion of ligneous matter has been found in the 

 ftoitiach of the animal of Teredo fiavalis, we are not to conclude 



it 



