iviii INTRODUCTORY OBSERVATIONS. 



mould where it Imbibes moft nutriment. Whence 

 does this mould originate ? Does the fifh, or 

 whatever it is, receive the feeds of the plant the 

 moment it comes in contaft with the air ? Do 

 they adhere to it without being wafhed off by the 

 water, until the conditions neceifary for their 

 expanfion concur in its death and tendency to pu- 

 trefaftion ? — Is it more reafonable to fuppofe the 

 feeds are difperfed through the water, continually 

 ready to be attached to the fubftances prefented^ 

 to expand and produce their plant. Philofophic 

 botanills may decide which of thefe opinions is 

 the more probable. But it would rather appear^ 

 that the feeds of mould are difperfed in water 5 

 for I have kept many aquatic animals, which I 

 can hardly think came to the furface during a 

 long time, and if they required air, perhaps ex- 

 trad:ed or received it from the furrounding wa- 

 ter : and, after death, luxuriant mould grew up- 

 on them. The thicknefs of this aquatic mould 

 has been confiderable, but never equally fo as 

 mould growing in the open air, which, it may be, 

 arifes from the difference of fpecies more than 

 from privation of circulating air. There is no' 

 leafon why mould (hould not thrive in water juft 

 as well as many plants, whofe natural aliment 

 is there, and abforb air in the fame manner ; be- 

 caufe there are fads which feem to prove the ex- 



iilence 



