132 BOTANICAL GAZETTE [AUGUST 
TABLE II. 
DurRaATION OF LiFE In Days. GROUP 2. 
3 Fe | 3 | : 
42) |= | 65 = le 
s2| 88|22|22|.8|22|- | 22! ag 
CULTURE SOLUTION. Boi es | fe | Fs] es] 5S | 5 | 25 a g 
A jeje [2 |e. |e |O |o 49 
| airy pees peau mene 
Sea water (total salt 2.7%)... .. 240 | 25 rr | 44 | 6 | 21 33+. 11. 
Artificial sea water: | 
I ¢ NaCl 3m/8 | 
we Mae 
38 “ MgSO agate artnet 220 | 20 | 74 | 44 | 6 |20 |33+]10 | 98 
ae RCI - | 
0° (CaCl es | 
Distilled water. 4.) 23. aes ales =) 34) 8 | 241-24 | 38 | 16 | 23 | 33 
Wap Wale re oS ee nie) 24 | 32| 33 | 23] 441 53 | 42 | 3t 
Natt 40/8... MP kt ET eR 5 fs | tts 
rooo ¢¢ NaCl 4 6 
a2. KCl ener ee Os) & + 64) 44) § [144 133+} 9 
1o “ CaCl, “c 
¥o00'"* Dist: HO : | 
22 “ KCl a (a4 ee rs 4% 4 1g 44 3 3 4 | 3 
2. The pure solution of each of the salts added to inhibit the 
poisonous effects of NaCl is itself poisonous at the concentration 
at which it exists after its addition, since the plants die in such a solu- 
tion much sooner than in distilled water.6 A mixture of solutions 
which are individually poisonous produces a medium in which the 
plants live indefinitely. 
That the plants die so quickly in solutions containing a single salt 
might be attributed to the fact that the osmotic pressure of some 
of these solutions is much lower than that of sea water. This suP-. 
position is disproved by the fact that in general the plants live longe 
in tap water than in any solution containing but a single salt, although 
the tap water has a lower osmotic pressure than that of any solu- 
tion used in the experiments. (The plants of Group 1 live longet 
in distilled water also. The tap water is to be regarded as a phy si: 
6 This statement does not apply in all cases to CaCl,, which is the least toxic of 
the salts employed and for some forms quite harmless in dilute solutions. 
