Lecture 2 — 45 — Micronutrient Elements 



able form for other plants than was originally present. 

 Plants of this kind are at times called selenium "con- 

 verters." Experiments have been made on certain 

 Astragalus species to ascertain if the plant itself ben- 

 efits from the absorption of selenium. Apparently 

 some species are favored in their growth by the pres- 

 ence of selenium in the medium. The suggestion has 

 even been made that selenium is possibly an essential 

 element for some species (Trelease and Trelease, 

 1938). 



One more case of lesser importance may be men- 

 tioned of the absorption by the plant of a chemical 

 element to the point of toxicity to animals. The report 

 has come from England that in some soils plants 

 absorb enough molybdenum to raise the plant's con- 

 tent of that element sufficiently to produce a patholog- 

 ical condition in the animals consuming the vegetation 

 grown on these soils. 



I should like to emphasize the interest inherent in 

 the broad question of the interrelation of soil, plant 

 and animal, which is of course not limited to the 

 micronutrient elements. Other inorganic plant nu- 

 trients and also organic substances synthesized by the 

 plant are involved. The importance of this field of 

 study has been considered by the Federal government 

 great enough to warrant the establishment of a new 

 laboratory at Cornell University with the specific ob- 

 jective of investigating the factors that govern the 

 quality of plant products from the point of view of 

 human and animal nutrition as distinguished from 

 quantitative yield. This is a practical objective, but in 

 the course of these and other researches of similar 

 trend, we may expect that our views of the nutrition 

 of both plant and animal will be widened, and that we 

 shall gradually perceive many unifying principles of 

 metabolism common to living organisms of different 

 categories. The micronutrient elements present one 

 interesting aspect of these convergent investigations. 



