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distributed that is generally imagined, and that the trap-rocks near 

 Edinburgh, and in the neighbourhood of the Clyde, as well as the 

 granites of Aberdeenshire, and the ashes of coal contain fluorides; so 

 that the soils resulting from the disintegration of those rocks cannot 

 fail to possess fluorides also. All plants, accordingly, may be ex- 

 pected to exhibit evidence of their presence, in the following portions 

 of their tissues or fluids : — 



1. In the ascending sap, simple fluorides. 



2. In the descending sap, in association with the albuminous vege- 

 table principles, and in the seeds or fruits, in a similar state of associ- 

 ation, fluorides along with phosphates. 



3. In the stems, especially when siliceous and hardened, fluorides 

 in combination with silica. The investigation is still in progress. 



Iodine in various Plants. 



' On the Presence of Iodine in various Plants, with some Re- 

 marks on its General Distribution ;' by Mr. Stevenson Macadam, 

 Teacher of Chemistry at the Philosophical Institution. The present 

 paper owes its origin to some observations lately made by M. Chatin, 

 of Paris, and communicated by him to the French Academy of Sci- 

 ences. 



Chatin is of opinion that in the atmosphere, in rain water and in 

 soils, there is an appreciable amount of iodine ; that the quantity of 

 this element present in one district differs from that in another ; and 

 that the relative amount of iodine in any one locality determines to a 

 great extent the presence or absence of certain diseases. For instance, 

 in the district of a country which he classifies under the general title 

 of the " Paris zone," the quantity of iodine present in the atmosphere, 

 in the rain water and in the soil, is comparatively great ; and to this 

 he ascribes the absence of goitre and cretinism : whereas in the zone 

 corresponding to that of the " alpine valleys " the amount of iodine 

 has diminished to one-tenth of that found in the " Paris zone ;" and 

 to this scarcity of the element he attributes the prevalence of goitre 

 and cretinism, which in that zone are endemic. Considering that the 

 subject was one of great importance, more especially if the conclu- 

 sions arrived at by Chatin (in reference to the functions fulfilled by 

 iodine in preventing the occurrence of the diseases referred to) could 

 be legitimately deduced from the experiments which he performed, 

 the author has this summer undertaken a series of analyses in reference 

 to the general distribution of iodine. Mr. Macadam's researches have 



