cffeveral Species of Pollen. 75 



the capfules. As the vegetable fsculum. whic*h conHas entirely of 

 this kind of matter feparated from the fokible and fibrous part, has 

 been long confidered as the fame fubftance, though obtainable from 

 different parts of vegetables, I extended the inquiry to tuberous 

 roots, and obtained a further confirmation of the identity of pollen 

 and faeculum. A potatoe feems to be almoft nothing elfe but an 

 affemblage of grains of faeculum, with their interftices occupied by 

 the juice. If this root be boiled or baked until it becomes mealy^ 

 the juice will no longer be found; and we might be at a bfe to 

 know what was become of it, if the microfcope did not {how that it 

 has entered into the grains of fa:culum, which are thereby greatly 

 diftended, as is, indeed, evident to the naked eye. The vital principle 

 is thus deftroyed ; for thefe bloated grains will not move in fpirits, but 

 give out a tinaure to it like other dead matter. By this means, and 

 the lofs of folidity, they are prepared for more eafy decompofition in 



the ftomach. . . 



Starch is abfolutely infoluble in water. If water contammg it be 

 made to boil, it becomes a jelly. I do not apprehend that a true 

 folution takes place even in this cafe. It appears that the fame 

 cffea is produced on the grains by the heat as by fpirit of wine. 

 They are difperfed into very minute particles; and the furface being 

 thus multiplied, a greater degree of attradion takes place between 

 the ftarch and the water, and the former remains fufpended. 



It appears to me to be worthy of future inquiry, 



1. In what parts of vegetables in general the pollen or fsculum 



is to be found. 



2. In what refpeds that which is fecreted on the anther differs 

 from that which is contained in the root, feed, or fap. In the leaf, 

 petal, bulb, fibre of the root, or other parts already brought to per- 

 feaion, I am inclined, from fome obfervation, to think it will not be 



met with. 

 VoL.V[. L 3. Whether 



