Ill Other Insectivorous Plants 57 



algae, and zoospores all alive, and insists that if the liquid 

 were really very digestive, these could not survive its 

 action. He sums up that the physiological use of pitchers 

 is a general one (associated with transpiration), and not an 

 exceptionally specialised digestive one, as so commonly 

 believed, and lays considerable stress on the comparatively 

 frequent recurrence of pitchers, monstrous as well as nor- 

 mal, among unassociated plant -forms as additional pre- 

 sumptive evidence of their relation to some constant rather 

 than exceptional function of plant-life. 



Again, M. Treub, the distinguished director of the 

 famous tropical garden of Buitenzorg (Java), has sug- 

 gested the internal roots of the Dischidia pitcher to be con- 

 nected with the reabsorption of water rather than of insect- 

 broth. In a book written before Hooker and Darwin had 

 made Nepenthes and its physiological analogues so famous, 

 Grisebach's Distributwn of Plants (vol. ii.), we find much 

 speculation on Nepenthes, apparently overlooked by subse- 

 quent writers, from which a couple of sentences may be 

 profitably extracted : "So considerable a loss of water 

 should accelerate the circulation of sap much more strongly 

 than would mere transpiration from the surfaces of the 

 leaves. ... All that the geographical distribution of 

 Nepenthes (Madagascar to New Caledonia) suggests as to 

 their organisation amounts to this, that they inhabit insular 

 climates, of which the atmosphere, abundantly laden with 

 water-vapour, impedes evaporation." 



A still more serious criticism is furnished by the latest 

 experiments on the digestion of pitchers and sundews — 

 those of Professor Dubois of Lyons, who has not only the 

 advantage of being apparently the only trained animal 

 physiologist who has yet worked at the question, but also 

 of having at his command the experience and the resources 

 of that vast development of bacteriological science which 



