May 28, 1920] 



SCIENCE 



551 



metliods used were less perfect than, those in 

 use to-day but even assuming that the analyses 

 are reasonably accurate, the varying propor- 

 tions and the various ingredients in the case 

 of different species and different analyses are 

 such that it is impossible to discern any rule 

 or law governing their absorption by the 

 plant. It is evident that certain mineral con- 

 stituents are necessary for the plant's growth, 

 but the minimum amount required of indi- 

 vidual elements or the relative amounts of 

 various elements apparently depend on a 

 number of variables, such as species and race 

 of plant, the soil, the season, the rainfall, the 

 state of cultivation, etc., to such an extent 

 that it is doubtful whether or not any sort 

 of rule governing these proportions can ever 

 be formulated. About all we can say is that 

 certain elements are necessary for the normal 

 growth of the plant and either the plant ob- 

 tains these at the proper time or it suffers 

 injury or death. 



Small wonder that the older chemists 

 failed to find the rule and all credit to them 

 that they did ascertain the main fact. 



Considering plants of all sorts, and all 

 parts of plants, silicon is the greatest variable 

 of all. It is invariably present but only in 

 small amount, even to a fraction of one per 

 cent, in fruits and edible grass seeds (grain), 

 whereas in the stalks of the same plants it 

 may constitute as much as seventy-five per 

 cent, of the ash. In the light of these facts, 

 it has been looked upon by some authors as 

 a material of construction (the first and most 

 natural thought) rather than as a physio- 

 logically functioning substance. This view 

 receives some confirmation from those ob- 

 vious cases in which silica serves as a struc- 

 tural support, as in the seom-ing rush and 

 diatoms. There can be no doubt that plants 

 acquired the silica habit early in their evolu- 

 tionary history and it yet may be found to 

 function physiologically, osmotieally or struc- 

 turally. It is difficult to think of an active, 

 surviving, plant organism absorbing and stor- 

 ing up such a substance or any substance 

 which has and can have no real and positive 

 use in its life cycle. Unless silicon functions 



in some way in plant metabolism or serves as 

 a building material, it is most difficult to ex- 

 plain the high relative portion of this element 

 in the grasses and scouring rush, the mod- 

 erate amounts in Artemesia and the almost 

 negligible quantity present in Prunus. 



It is interesting to visualize the activities 

 of the growing root tip as it projects itself 

 among the sand grains, moving under the re- 

 actions of the various tropisms in such wise 

 that the weal of the growing plant is con- 

 served; turning as necessity arises first in one 

 direction, then in the other, but on the whole 

 maintaining its direction, since there are no 

 serious obstructions in the dune soil; wedging 

 its way molelike undergrovmd, expanding, 

 holding fast; neglecting grains of silica, lying 

 close to potash silicates, absorbing chance 

 molecules of calciimi bicarbonate and phos- 

 phates, furnishing the chemical means if need 

 be, of bringing the insoluble substance it re- 

 quires into solution; keeping the cell pumps 

 going to furnish the water supply to the plant 

 in time of rain or drought; a very center of 

 ceaseless, slow, sure activity, in which all the 

 forces of nature seem to be at work to main- 

 tain a useless bitter plant. 



W. D. ElCHAEDSON 



Chicago, III. 



THE UTAH ACADEMY OF SCIENCES 



The thirteenth annual convention of the Utah 

 Academy of Sciences was held in the physics lec- 

 ture rooim of the "University of Utah at Salt Lake 

 City on April 2 and 3, 1920. 



At *h6 business meeting at the close of the ses- 

 sion, April 3, the following memjbers were elected 

 to fellowship in the Academy: O. W. Israelson, 

 Utah Agricultural College, Logan; T. B. Brighton, 

 University of Utah, Salt Lake City, and R. A. 

 Hart, Springville. 



The following were elected to membership: Dr. 

 E. L. Quinn, University of Utah; Dr. E. E. Er 

 ricksen. University of Utah; Orin A. Ogilvie, Uni- 

 versity of Utah; Wm. Z. Terry, Ogden; Geo. P, 

 Unseld, Salt Lake City, and Albert S. HutcMns, 

 Spriagville. 



The constitution was amended raising the an- 

 nual dues to two dollars, effeeitive for the present 

 year. 



