Note 42 — Prop. IV.—That some few remedial agents act locally on the mucous surface, either before absorption, or without being absorbed at all. That they are chiefly as follow:— (continued 3)

I have just said that Neurotic medicines influence those functions which are attributed to the nervous system. Now there can be no reasonable doubt that they actually influence the nerves. But it is worth while to notice here the curious fact that the same agents have been found to paralyze the irritable or contractile tissues of certain vegetables. Professor Marcet of Geneva first noticed that the vapours of Chloroform and Ether affected the leaf of the sensitive plant so as to prevent it from contracting at the touch, but without at the same time perceptibly injuring its structure. I have produced the same effect on a species of Acacia, which naturally closes its leaves at the approach of night. The leaf experimented on remained open, while the others closed. After a certain time it recovered. Solutions of Morphia, Conia, and other sedatives, have been found to produce the same result. Now the existence in plants of nervous tissues is not usually admitted. How then are we to explain the analogous action of these paralyzing Neurotics on animals and vegetables? Possibly they may be capable of acting directly on contractile or irritable tissues in both cases, without necessarily influencing the nerves in order to produce paralysis.