FUNCTION.] PROVED BY ACTION OF POISONS. 151 



was found to produce effects similar to those of arsenic ; but 

 no effect was produced upon a Cherry tree, by boring a hole 

 in its stem, and introducing a few globules of liquid mercury. 

 Tin, copper, lead, muriate of barytes, a solution of sulphuric 

 acid, and a solution of potash, were found to be all equally 

 destructive of vegetable life ; but it was ascertained, by means 

 of sulphate of magnesia, that those mineral substances which 

 are innocuous to animals are harmless to vegetables also. In 

 the experiments with vegetable poisons, the Bean plants were 

 carefully taken from the earth, and their roots immersed in 

 the solutions used. It had been previously ascertained, that 

 plants so transplanted and placed in water, under ordinary 

 circumstances, would remain in excellent health for six or 

 eight days, and continue to vegetate as if in the earth. A 

 plant was put into a solution of nux vomica at nine in the 

 morning : at ten o'clock the plant seemed unhealthy ; at one 

 the petioles were all bent in the middle ; and in the evening 

 the plant was dead. Ten grains of an extract of cocculus 

 suberosus, dissolved in two ounces of water, destroyed a 

 Bean plant in twenty-four hours; prussic acid produced 

 death in twelve hours, laurel water in six or seven hours, a 

 solution of belladonna in four days, alcohol in twelve hours. 



From the whole of his experiments, Marcet concluded 

 1st, That metallic poisons act upon vegetables nearly as they 

 do upon animals : they appear to be absorbed and carried 

 into different parts of a plant, altering and destroying the 

 vessels by corrosion. 2ndly, That vegetable poisons, espe- 

 cially those which have been proved to destroy animals by 

 their action upon the nervous system, also cause the death of 

 plants : whence he infers that there exists in the latter a 

 system of organs which is affected by poisons, nearly as the 

 nervous system of animals. 



These facts have been confirmed by others. In their 

 experiments with gases, Turner and Christison remarked that 

 " the phenomena, when compared with what was observed in 

 the instances of sulphurous and hydrochloric acid, would 

 appear to establish, in relation to vegetable life, a distinction 

 among the poisonous gases, nearly equivalent to the difference 

 existing between the effect of the irritant and the narcotic 



