Page:Transactions of the Linnean Society of London, Volume 6 (1802).djvu/99

Rh the capsules. As the vegetable fæculum. which consists entirely of this kind of matter separated from the soluble and fibrous part, has been long considered as the same substance, 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 fæculum. A potatoe seems to be almost nothing else but an assemblage of grains of fæculum, with their interstices 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 loss to know what was become of it, if the microscope did not show that it has entered into the grains of fæculum, which are thereby greatly distended, as is, indeed, evident to the naked eye. The vital principle is thus destroyed; for these bloated grains will not move in spirits, but give out a tincture to it like other dead matter. By this means, and the loss of solidity, they are prepared for more easy decomposition in the stomach.

Starch is absolutely insoluble in water. If water containing it be made to boil, it becomes a jelly. I do not apprehend that a true solution takes place even in this case. It appears that the same effect is produced on the grains by the heat as by spirit of wine. They are dispersed into very minute particles; and the surface being thus multiplied, a greater degree of attraction takes place between the starch and the water, and the former remains suspended.

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 respects that which is secreted on the anther differs from that which is contained in the root, seed, or sap. In the leaf, petal, bulb, fibre of the root, or other parts already brought to perfection, I am inclined, from some observation, to think it will not be met with. 3. Whether