430 



Phytin on the Groivth of Seedlings 



[Mar. 



Solution. The rods were so adjusted in the perforations that the 

 roots were immersed in the Solution, but the cotyledons were not 

 in contact with it. Four seedlings were suspended in each beaker. 

 The roots at the beginning differed in length, as much as fifteen 

 millimeters in some cases. An attempt to minimize the effects of 

 such variations was made by placing two shorter roots with two 

 longer ones in the same beaker, or eise by choosing what seemed 

 to be the average; four long roots or four short roots were never 

 suspended together. At intervals of one to three days, all the seed- 

 ling roots were measured. 



Variations in growth under " control " conditions. The ex- 

 periments were carried on before a large window, in a separate 

 room, under as favorable conditions for growth as could reasonably 

 be expected. Irregularities in growth were noticed from the begin- 

 ning, due to unknown factors. Ordinary distilled water was used 

 in making up the Solutions and may account for some of the differ- 

 ences. The chemicals employed were pure, and in each case taken 

 from a dilute stock Solution, with the exception of the calcium sul- 

 phate and calcium phosphate, which were obtained from large bot- 

 tles of saturated Solutions havingexcesses of the salts on the bottoms. 

 The calcium sulphate supply was renewed by adding distilled water 

 to the residue in the bottle after each planting, and shaken several 

 times before the day for starting the next set, the required amount 

 being then carefully decanted so as to prevent admixture with the 

 Sediment. One bottle of the calcium phosphate Solution sufficed for 

 the whole experiment. Characteristic irregularities are indicated in 

 the following tables, the first of which shows the rate of growth of 

 seedlings suspended in a one-half saturated calcium sulphate Solu- 

 tion ; the second in a 0.06 per cent. calcium nitrate Solution. 



TABLE I. 



"Normal" Growth in 0.12 per cent. CaS0i,2lii0 Solution 



Date of Planting, 1911 



March 19 

 April I . . 

 April 24. 

 May 5 . . . 



Rate of Growth per Plant in Millimeters 



ist Day 



12 

 8 



15 

 16 



2d Day 



28 

 12 

 16 

 16 



6th Day 



6 

 9 

 9 

 8 



Average per Day 

 for First Six Days 



20.6 



8.9 



16.S 



16.0 



