[39] "The state or condition of formation or decomposition of a body, the state of change of place or motion in which its particles are, exerts an influence on the particles of many other compounds, if in contact with them. The latter are brought into the same state; their elements are separated and newly arranged in a similar way, and acquire the power of entering into combination, a power which they did not, under similar circumstances, previously possess."--_Liebig's Animal Chemistry_, vol. i. p. 194. [40] Dr. Mead, in 1751, recommended the employment in Scrofula of burnt sponge, and a pill containing "sublimed Mercury" and precipitated Sulphuret of Antimony. Plummer's pill is often prescribed in these cases at the present day. [41] Among these, Dock, Sorrel, Wood-sorrel, and Stonecrop, may be mentioned. Such herbs have been long employed, and recommended by authority. Dr. Mead, in 1751, recommended Scurvy-grass, Lettuce, and Brooklime. He also made particular mention of the _Herba Britannica_, which seems to have been the great Dock, Rumex hydrolapathum. The same physician appears to have anticipated some of the modern applications of Lemon juice. He employed it in liver-diseases generally, among which he included a number of dyspeptic and gouty disorders. He gave it in six-drachm doses; and says that he employed also in similar cases _saponaceous_ medicines, and rhubarb. These remedies, apparently heterogeneous, were recognised then, as now, to be useful in the same cases. For we have just seen that Lemon-juice, Alkalies, Cholagogues, and Tonics, are all more or less applicable in diseases of the Arthritic group. [42] 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. [43] Turner's Chemistry, 7th edit., p. 995.