Francis E. Lloyd — 208 — Carnivorous Plants 



though the difficulty of confining the acid to the hairs alone, which is 

 obvious, throws some doubt on the conclusion. 



Other organic substances: — When exposed to commercial for- 

 malin, the trap becomes immobilized in 35-45 seconds. During 

 this period, if stimulated mechanically the traps will close. In some 

 cases the traps close on direct stimulation by the reagent about 15-30 

 seconds after immersion. Because overtaken by immobilization, the 

 closure is never complete. In dilute formalin, the closure may be 

 complete, since immobilization does not overtake the traps quickly 

 enough. This is explained by the toxic effect overtaking the epi- 

 dermis cells before the reagent can enter by way of the sensitive 

 hairs. Ashida also reports the recovery of sensibility in 20 minutes 

 after immobilization by exposure to concentrated formalin for 45 sec- 

 onds, indicating that the injury to the epidermal cells is to some 

 extent reversible. Such traps may close and narrow, perhaps as an 

 after effect of adherent formalin for i minute, hence completely im- 

 mobilized traps close and narrow in water 5-10 minutes later in spite 

 of complete immobilization. If entirely killed by longer exposure, no 

 movement occurs. 



Such experiments are puzzling, but indicate at least that the 

 toxic effects are realized somewhat slowly, and that the stages of 

 turgor reduction realized in the meantime are such as to allow the 

 working of the mechanism of closure, partially or completely. The 

 slow penetration must be due to the resistance of the cuticle. Ashida 

 recognizes two effects, stimulation and immobilization, on the rate of 

 the latter depending the ability to respond, through the action of the 

 sensitive hairs, into the hinge cells of which the reagent can penetrate 

 more quickly. 



In ethylalcohol 10-40 percent by volume, traps close spontane- 

 ously in from about i to 90 minutes, according to age. Curiously 

 enough, in solutions stronger than 40% closure occurs in two steps, 

 both sudden, separated by a pause. 



In saturated chloroform-water, most traps close within i minute, 

 some quickly, some slowly and some irregularly. Restoration to water 

 procures no further activity, and they die. Czaja had previously 

 obtained similar results. He found also that, after treatment with 

 ethyl ether at similar concentrations, return to water restored the 

 normal activity. The effect of narcotics, he says, is at first stimulative, 

 then destructive. He obtained similar results with methyl and ethyl 

 alcohols. 



The addition of peptone or egg-albumin to the culture medium 

 causes the traps to close and narrow, as also if a fragment of fish 

 or meat is fed to the trap. Closure follows then from mechanical 

 stimulation, and narrowing results from the chemical stimulation. 

 Gelatin and coagulated egg-albumin do not stimulate beyond the 

 shutting stage, since they do not stimulate chemically (Ashida). 



Digestion and absorption. — There is not much doubt that Aldro- 

 vanda digests prey and absorbs the products of digestion. All ob- 

 servers have seen that the bodies of prey, except the hard parts, 

 disappear, and Darwin did a few experiments which convinced him 

 that absorption takes place. The evidence is, however, not complete, 



