Cuar. VIO. CONCLUDING REMARKS, SALTS. 187 
the corresponding salts of potash do not cause inflec- 
tion, and some of them are poisonous. Two of them, 
however, viz. the oxalate and iodide of potash, slowly 
induced a slight and rather doubtful amount of inflec- 
tion. This difference between the two series is inter- 
esting, as Dr. Burdon Sanderson informs me that 
sodium salts may be introduced in large doses into 
the circulation of mammals without any injurious 
effects; whilst small doses of potassium salts cause 
death by suddenly arresting the movements of the 
heart. An excellent instance of the different action 
of the two series is presented by the phosphate of 
soda quickly causing vigorous inflection, whilst phos- 
phate of potash is quite inefficient. The great power 
of the former is probably due to the presence of 
phosphorus, as in the cases of phosphate of lime and 
of ammonia. Hence we may infer that Drosera cannot 
obtain phosphorus from the phosphate of potash. This 
is remarkable, as I hear from Dr. Burdon Sanderson 
that phosphate of potash is certainly decomposed 
within the bodies of animals. Most of the salts of 
soda act very rapidly ; the iodide acting slowest. The 
oxalate, nitrate, and citrate seem to have a special 
tendency to cause the blade of the leaf to be inflected. 
The glands of the disc, after absorbing the citrate, 
transmit hardly any motor impulse tc the outer 
tentacles; and in this character the citrate of soda 
resembles the citrate of ammonia, or a decoction of 
grass-leaves; these three fluids all acting chiefly on 
the blade. 
It seems opposed to the rule of the preponderant 
influence of the base that the nitrate of lithium 
causes moderately rapid inflection, whereas the acetate 
causes none; but this metal is closely allied to sodium 
