124 Effects of Poisons on Living Vegetables. 



the river to its source, in quest, among the distant mountains of 

 the place, from whence it came. Though the explorer might be 

 gratified in finding his search successful, and meet in some rent 

 and broken ravine through which the waters are now rushing, 

 with the veins of quartz, displaying to broad view their metallic 

 riches ; yet let him seek to effect his object, under similar cir- 

 cumstances, in another, and perhaps adjacent district, he will lose 

 himself in an investigation of a formation which never yet, or 

 ever will be found to contain gold. He will meet with the de- 

 bris of rocks long ago passed away in the conflicts of the elements ; 

 he will meet with evidences of a state of things which now no 

 longer exists on the surface of these wild and singular regions. 

 In some tracts of land the gold will be found disseminated poorly 

 yet regularly in layers ; in others it will be disclosed in some pe- 

 cuUar position, en masse — in one solid lump — in little circles of 

 a few feet, as if deposited by the vortex of some minor whirlpool ; 

 and in fine, in such occasional directions as to set all attempts at 

 theory at defiance. 



" Data, nevertheless, have presented themselves during the 

 progress of gold mining in various countries, which have proved 

 highly interesting, and of the greatest service in assisting the 

 investigation of the position, nature, and quality of gold de- 

 posits." 



ON THE EFFECTS OF VARIOUS POISONS ON LIVING 

 VEGETABLES. 



By Richard Harlan, M. D. Surgeon to' the Philadelphia Alms-house Infirmary, 

 Member of the Royal Academy of Medicine of Sweden, &c. &c. 



I completed last year the following series of experiments, in 

 order to test the powers of vegetable life in resisting the effects 

 of vegetable and mineral poisons. The positive nature of the re- 

 sults which were obtained, is calculated, in my opinion, to throw 

 considerable light on the physiology of plants ; a department of 

 science, at the present time, too much neglected, even by the 

 members of the medical profession, and by the practical agricul- 

 turists, for the most part, entirely overlooked. 



The application of certain poisons to plants and flowers, in or- 

 der to destroy noxious insects, is not unfrequently recommended ; 

 and doubts have been expressed as to the injury that might occur 



