TRUE & HARVEY: ABSORPTION OF CALCIUM SALTS 509 
TABLE 2 
Net Absorption by Squash Seedlings from Solutions of Calcium Sulphate 
Original Concentration Minimum Concentration Maximum Absorption 
as Grm. Norm. as Grm. Norm. as Grm. Norm. 
CaSOs X10-6 CaSO; X 10-6 CaSO; X 10-8 
ARON ere eres oo oes Se AGiGn eet eee ew — 38.7 
BIC OSL ents con eas an se Cop [as BE ie ne on ae ee — 409.32 
Rij Oa frst ste tae le eons See BOLO sar eaisee ee eens ee a Aad. 
GING i ie ge eee en eae 217 (AS Yies PREY ete Fey hy tio be = 334 
Banco serve ot agar cts & Ses BT eT ep ee 14.4 
ONCO Bre top cy iaetialanc meine seus 7 OS Or Pas eck eae ee aaa 25-9 
11/10 ER Ae eo pe AU GLO en pet eee 57-4 
EQ Hedin a: oiekest ic st Ak a keewe TAG 2M 2. ee 51.3 
ATE) Se ots ihn csi node, Secu Move sol BERR seys Ma ceva ons 57 
ANT APs oA Rt eds Ae Seed ct Ba5sS tit othe eae Oe 78.8 
GoGy eek as een a aes Eases fe AAS pikes Bleach Mae 87.3 
OSAP Am TS ee tk. he et Sees 5287 yee ee 125-7) 
FAT Cee Oe er ene, NE GES 0) eee oes 112.0 
SALA aioe He cht oy ee TORO nea tise. cet eee 119.8 
CALCIUM CHLORIDE 
In the foregoing experiments we have had to do with salts in which 
both cation and anion are required for the normal growth of higher 
plants, and we find squash seedlings behaving toward them in sharply 
contrasting ways. From solutions containing G and NO3 i ions root 
absorption is very active. When Ce ions are accompanied by SO, 
ions, however, absorption is relatively small. 
In view of these facts it is a matter of no small interest to test the 
behavior of plants in solutions in which the Ca ion is accompanied by 
the Cl ion. 
A series of solutions was made up containing a graded series of 
concentrations running up to 582.4 grm. norm. in a million liters. 
The experiment ran from Aug. 9 to Aug. 26, 1916. A graphic record 
of the concentration changes observed is shown in the accompanying 
group of curves (Fig. 3). It is perhaps hardly necessary to do more 
than to point out certain of the more important features to be observed. 
In general a very striking similarity to the corresponding set of curves 
obtained from Ca(NO3)2 solutions may be noted. The solutions hav- 
ing an original concentration of 32.5 and less show a loss of electrolytes 
for the first five or six days after which time absorption begins and 
continues until near the end of the experiment, but in none is the 
loss during the early days fully regained, although in that originally 
containing 32.5 grm. norm. the net loss is practically negligible. 
At this concentration we find again evidence of a critical concentration 
of some sort below which the plants can not absorb and above which 
