120 



HUTCHINSON'S POPULAE BOTANY 



of the victims, for they have found only the hard parts of the prisoners 

 remaining after a short period of incarceration. 



The accompanying photographs of the Toothwort have peculiar interest, 

 because they were taken in a Surrey lane where John Ray (16281705) 

 recorded the plant as growing in his time. The plant photographed is in 

 all probability a direct descendant of the plants he noted. Figs. 155, 157. 



It may be asked. How is it that the fluid from the soil is able to force its 

 way through the membranous cell-walls of the root-hairs and to pass upwards 

 into the plant '? The question suggests another, namely, How is it that water 

 is drawn up into a piece of loaf-sugar or a sponge ? though by fencing the 

 first question in this manner one is only suggesting a solution to the tail-end 

 of the difficulty, nor this, unless something is known of capillary attraction. 

 But how is it that the fluid of the soil gains entrance into the closed 

 cells ? A merely verbal explanation, however clear, would be dry and unen- 

 lightening. We might talk about endosmose and exosmose and the power 

 of passing through porous diaphragms for hours, and still fail to convey 

 a definite impression 011 the subject. An experiment in this case will 

 save a world of laborious explanation. For this experiment nothing more 



is required than a bowl of distilled 

 water, some sugar in solution, a small 

 length of glass tubing, and a couple of 

 pieces of bladder to close up the ends. 

 The experiment is performed in 

 the following manner: Close up one 

 end of the tube with a piece of bladder 

 and pour in the solution of sugar ; then 

 close up the other end, and immerse 

 the whole in the bowl of water. It 

 will presently be found that the bladder 

 at both ends has become distended, in 

 consequence of an increase of volume 

 of the fluid in the tube, the increase 

 being due to an inflow of the distilled 

 water in which the tube is immersed. 

 This transmission of fluid through a 

 porous partition from the exterior to 

 the interior is called endosnwse (Greek 

 endcm. within : osmos, impulsion). On 

 applying a little of the distilled water 

 to the lips, it will be found to have 



Photo by] is. L. Bastin. acquired a slightly sweet taste, a small 



FIG. l54:.Cephalotu8 follicularis. portion of the sugary solution having 



Interior of a pitcher of this little Australian Pitcher- passed OUt thrOUffll the bladder. Here. 

 plant. The entire plant is shown in fig. IS. Vote , 



the dead insects. then, is evidence that two currents, 



