TRACE ELEMENTS IN ANIMALS 



131 



Inspection of this shows that although the species used exhibit 

 a wide range in sulphur and selenium uptake, the ratio of 

 sulphur to selenium absorbed is roughly the same in all. 



Table XVI. Content of sulphur and selenium of a number of 

 crop plants one month old. (From Hurd-Karrer) 



Species 



Brassica oleracea capitata (cabbage) 



B. oleracea botrytis (cauliflower) 



B. nigra (black mustard) 



B. napus (rape) 



B. oleracea acephala (kale) 



Linum usitatissimum (flax) 



Helianthus annuus (sunflower) 



Trifolium pratense (red clover) 



Vicia villosa (vetch) 



Lactuca sativa (lettuce) 



Triticum sativum (wheat) 



Secale cereale (rye) 



Glycine hispida (Soya bean) 



Zea mais (maize) 



Sorghum vulgare 



Hurd-Karrer also found that the sulphur /selenium ratio was 

 practically the same for stems and leaves and also that the ratio 

 depended on the relative amounts of sulphur and selenium in 

 the soil. If the former remained the same while the selenium 

 content was varied, the sulphur/selenium ratio in the plant rose 

 with a fall in the selenium content of the soil. Thus, with a 

 sulphur content of the soil of 0-06 per cent, the average ratio 

 of sulphur to selenium in the plants was found to be 114 when 

 the selenium in the soil was 3 p. p.m., but when this latter was 

 increased to 5 p. p.m. the sulphur/selenium ratio in the plants 

 was only 22. 



These results are readily understandable in view of the 

 chemical similarity of sulphur and selenium. They indicate very 

 definitely a way of reducing the selenium content of plants 

 growing on seleniferous soils. 



For a good detailed account of the earlier work on selenium 

 poisoning reference may be made to a review by Trelease and 

 Martin (1936). 



The Scouring of Cattle on the Teart Lands of Somerset. 

 On certain soils derived from the Lower Lias, where this is 



