Chapter II — 33 — Sarracenia 



did only two superficial experiments, one proving to his mind that 

 diastase, and a second that a pepsin is present. 



Following GoEBEL, Lambert (1902) showed absorption to take 

 place in certain regions, by following the entrance of methylene blue 

 or fuchsin. That digestion occurs was no more than a conviction 

 without proof. Fenner (1904) like Schimper observed that absorp- 

 tion takes place and is followed by cytological changes in the epider- 

 mal cells. He observed quantitatively considerable amounts of fluids 

 absorbed. As to digestion he expressed the opinion that Sarracenia 

 flava is an insectivorous plant with a digestive enzyme. Robinson 

 (1908) found evidence that sucrose and starch can be digested to, 

 presumably, simple sugars by the pitcher fluid, confirming Zipperer 

 as to starch, but none that there is either fat or protein digestion. 



Thus stood the evidence when in 1918 Hepburn, St. John and 

 Jones started their exhaustive studies on these physiological questions 

 presented by Sarracenia (and Darlinglonia, mentioned elsewhere). 

 These authors did an immense lot of work and travelled extensively 

 for the purpose of doing field experiments. To their results we now 

 turn. 



For the purpose of learning about the presence or absence of 

 digestion, they examined 5. flava, Drummondii, Sledgei, rubra, minor, 

 psittacina and purpurea. Tests were made on the fluid from both 

 unopened and opened pitchers, with and without the addition of weak 

 acid (HCl) and alkali (sodium carbonate), and always in the presence 

 of trikresol as a bactericide. Carmine fibrin was used as a substrate 

 in the field, and this, edestin, casein and coagulated egg albumin in 

 the laboratory. The evidence was strengthened by duplication, trip- 

 lication, or even quadruplication of the tests. Generally composite 

 samples of fluid drawn from a number of pitchers were used. All 

 experiments were done quantitatively, even to measuring the amount 

 of substrate, a matter of importance often disregarded. 



In S. flava a protease was shown to act on fibrin in both closed 

 (that is, still unopened) and open pitchers. It is more active in weak 

 acid (0.2%), than in weak alkali, but there was no action in their 

 absence. Edestin was digested in 1.5 to 2 hours. The fluid from closed 

 pitchers was vigorous, acting completely in 30 min. at 37.5° C. and 

 almost so at room temperature. Casein was partially digested in 2 

 hours. With coagulated egg-white negative results only were obtained. 



S. Drummondii and S. Sledgei. — When the fluid of closed pitchers 

 was acidified and then tested the results were purely negative. With 

 that of open pitchers, six experiments of eight were negative, but 

 partial or complete digestion occurred in two on sustained exposure 

 (49-57 days). When neither acid or alkali were added the fluid of 

 closed pitchers failed to act even after 50-55 days in four experiments; 

 in two others digestion occurred in 7 and 21 days respectively for S. 

 Drummondii. For 5. Sledgei one experiment was negative, while 

 others acted slowly but completely in 37 to 49 days. The results 

 stand in marked contrast with those in which the fluid was modified 

 by alkali, showing that digestion occurred in 1.5 to 18 days in 20 ex- 

 periments, while in two others it required 32-36 days, the slowness 

 being due to a reduced concentration of sodium carbonate, which 



