Page:Transactions of the Linnean Society of London, Volume 6 (1802).djvu/96

70 that the pollen of vegetables is in all cases similarly acted upon by water and by spirit of wine, it will follow,—

1. That each grain of pollen in the anther is an organic body, variously constructed in various species, and containing

a Vessels or pores capable of imbibing water, of distending thereby and con trading again when It quits them; in which particulars they resemble sponge, &c.

b A parenchyma, consisting of some substance (of greater specific gravity than water, and insoluble therein), which is emitted with a greater or less degree of force when the stimulus of alcohol is applied to the absorbent vessels. This substance is either in part soluble in alcohol, or the grains contain

c An essentiai oil or resin, to which they owe their colour and odour.

2. That there exists in the grains of pollen, in a very eminent degree, that property of vegetables called irritability, which they are capable of retaining for a certain time after separation from the anther.

3. That alcohol is the proper stimulus by which this irritability may be excited, and the texture of the pollen in some manner developed in consequence thereof. I prefer this method of accounting for the appearances that take place when the pollen is immersed in spirit to another that might be supposed on chemical principles, being assured, that any one who has once inspected the process will be satisfied that something more than mere solution or chemical decomposition takes place therein, and that the vital principle of the pollen is the chief agent.

The liquor from the tube of the pistil and the solution of sugar were, indeed, found to bring on the evolution of the pollen of Cactus flagel. in slower manner than spirit; but when we consider how speedily