50 



place through anolher lube nol shown in Ihe fig. Even when iilled 

 with Ihe envelojie of water. the weighl of Ihe apparalus is not so 

 greal Ihal il cannol easily be carried about by means of a metal 

 handle altached by corresponding loops to the oulside of the box. 

 As the objects of my experiments I used cul-olT leaves, the stalks 

 of which were inlroduced into narrow glass tul)es, filled with water. 

 Tube {gl} serves for the introducing and withdrawing of the leaffrom 

 the ap|)aratus. This lalter tube is of glass, bas a diameter of about 

 4 cm. and a lenglh of about 15 cm., and is firmly fixed by means 

 of cork and paralTin inlo a somewhat wider metal tube. Into the 

 outer end of the lube Ihere is filted a rubber stopper (/.,), through 



^O—ij-M 



I. 



^ 



I. 



M 



Fig. 1. Apparatus for e.stimation of assimilation and respiration in plants. I, the 



apparatus in transverse .section, on a ten tinies rediued scale. II and III show the 



manipulations for attaching the object, IV the titration vessel. 



the middle of which runs a rod (/^) of galvanised iron, 3 mm. thick. 

 This rod is provided wilh a handle, and can be slowly pushed 

 hackwards and forwards through the stopper (ef. II and III). The 

 other end of the rod is threaded through anolher rubber stopper 

 (r^), which lils the inner end of the glass tube and closes this her- 

 melically when the rod is withdrawn. 



The objecl of experiment (x) is attached by means of small rubber 

 rings to the iron rod. When the rod is pushed into position I, the 

 leaf is therefore within the assimilation-chamber: when the rod is 

 ^vilhdra^^n in Ihe position II, the leaf is enclosed in the glass tube 



